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The Heart Principle

(The Kiss Quotient #3)

4.04  ·  Rating details ·  67,695 ratings  ·  10,313 reviews
A woman struggling with burnout learns to embrace the unexpected—and the man she enlists to help her—in this new New York Times bestselling romance by Helen Hoang.

When violinist Anna Sun accidentally achieves career success with a viral YouTube video, she finds herself incapacitated and burned out from her attempts to replicate that moment. And when her longtime boyfriend
Paperback, 339 pages
Published August 31st 2021 by Berkley
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Popular Answered Questions
Marie L Hi! The books work well as stand alones. In fact, in the second book the first book's main characters are only mentioned and "show up" once, if I reme…moreHi! The books work well as stand alones. In fact, in the second book the first book's main characters are only mentioned and "show up" once, if I remember correctly.
Btw, despite the first book's premise, it isn't any more graphic (or has more sex scenes) than the second one. It does have more scenes of a sexual nature, but they aren't graphic, more sensual/erotic/emotional. I don't know if that makes sense lol I don't want to spoil the book in case you change your mind. ;)
To me, who has next to no experience with people on the spectrum, it was very eye-opening to see someone's life on the spectrum from a female perspective - and I found it a gorgeous read overall. <3 (less)
Dabarai Yes, the author confirmed it on instagram.

Community Reviews

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Average rating 4.04  · 
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 ·  67,695 ratings  ·  10,313 reviews

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Emily May
Apr 24, 2019 rated it it was amazing
Shelves: 2021, arc, romance
How much of what people say is genuine and how much is politeness? Is anyone really living their life or are we all reading lines from a giant script written by other people?

I gave The Kiss Quotient and The Bride Test five stars, so now I need a sixth star to emphasise how Hoang's latest book was my absolute favourite. The Heart Principle was everything I wanted, and so much more. Hot, sweet, sad, deeply personal. This is a big claim, but it genuinely might be my favourite romance novel ever
Jul 11, 2021 rated it it was amazing
Shelves: 2021-favorites
***ARC provided through NetGalley***

Don’t mind me, just sitting here, MIND BLOWN by this book. Seriously, someone go find some goddamn paper towels because there are chunks of brain matter all over the floor. My relationship with this trilogy has been a little rocky in the past but The Heart Principle said “fuck ur expectations” and then proceeded to ruin my life.


The story follows Anna, a professional violinist who is experiencing creative burnout after a video of her performing goes viral on Y
Aug 25, 2021 rated it liked it  ·  review of another edition
I like that this book tackled heavier subjects and focused on the main character’s development with the romance taking a back burner in the second half of the story. However, the simplicity of the writing didn’t develop the plot points deeply enough for my liking, despite the author writing from a personal place. The romance and overall conclusion also felt rushed. Lastly, I wish the love interest Quan had more development for his own story if we were going to see the protagonist go through a lo ...more
Aug 05, 2021 rated it it was amazing
I am a fan of Hoang’s writing and this was a great novel. Anna is one of the author’s stronger characters and this was as much a novel about a woman coming into herself and learning to manage a later in life autism diagnosis as it is a sexy romance novel. It was also great to see Quan and Michael again. A very affecting novel I found satisfying in every way.
chan ☆
Aug 31, 2021 rated it liked it
i have very conflicting feelings about this book and simply rating won't sum up my feelings.

to start, when i finished this book i felt... angry. angry for anna, angry for quan, and then angry that no one properly warned me what this book was all about. i read reviews and i certainly got the feeling that this wasn't going to be a romcom but i didn't expect to come away from this reading experience, frankly, traumatized.

reading that back, it's sounding a little melodramatic and maybe i'm just the
Mar 13, 2019 rated it it was amazing
Shelves: arc-books
Two individuals from different worlds that cross paths towards the way of healing, and learning more about each other for the better of their individual selves...

Years of anticipation made us all Helen Hoang lovers crave Quan's novel for a very long time. Now that's finally here there is a lot that shocked me while reading his book. This is not just a romance novel that touches base on two characters that find the best of each other both physically and emotionally. This is also a story of a
Nilufer Ozmekik
Dec 12, 2019 rated it it was amazing
Happy pub day! ❤️❤️❤️❤️❤️

Sigh-smile-cry : I’m repeating this routine for last 28 hours after finishing this book because I keep replaying the special moments of the story on my mind. It affected so much more than I expected!

I can honestly say two things about this freaking brilliant story: it’s the most intense, sad, emotional book of the series with most adorable characters.And it’s also best of best book of the series.

Yes, it extremely sentimental, touching your soul, making you sad and stabb
Aug 13, 2021 added it
I don't even know how to begin to rate or review this book, because this isn't the story I signed up to read.

First and foremost, I do want to thank Helen Hoang for being courageous enough to write this story. It's clear that this is a deeply personal book for her, and in the author's note, she said as much, calling this "half a memoir."

I went into this expecting a sweet and heartfelt romance. I'd read both of Hoang's previous two books, and loved them for their diverse and nuanced depiction of p
Feb 20, 2019 rated it really liked it
Quan finally getting his own story

I have been eagerly awaiting Quan's book since I first read about him in The Kiss Quotient, a few years ago. I always knew that his book was going to be amazing because he was just such an amazing character and I was totally right! This book was by far my favorite of the three books in this series.

As always, Helen Hoang fills her books with complex and compelling characters going through their own journeys of personal and emotional growth, as well as fallin
Taylor Reid
Apr 07, 2021 added it
Shelves: 2021
When Anna’s boyfriend declares he wants an open relationship, her hurt and anger propel her to have a one-night stand. But things don’t go according to plan once she meets Quan. After multiple failed attempts to have their one night only, they quickly realize their connection is deeper than anticipated. If you’ve read Helen's other books in the trilogy, you might be surprised by just how emotionally raw this one is. But if you’re prepared for the journey, it’s a great one. ...more
Helen Hoang
Jul 14, 2021 added it  ·  (Review from the author)
For those who are interested, I'd be honored to sign a copy of this book for you. You can order here (they ship internationally): https://www.therippedbodicela.com/pro...

Thank you to everyone who's reading and reviewing this book! Truly, thank you from the bottom of my heart. This is an extremely personal book for me, and it means the world to me that you're gifting me with your time. I wish you well. <3
Chelsea (chelseadolling reads)
Aug 06, 2021 rated it it was amazing
Shelves: read-in-2021
Just sobbed my way through the author's note and I am not okay wow this was absolutely Helen Hoang's best book yet. So very different from her previous work, but in the best way. I can definitely see why this book wouldn't work for everyone; it is extremely different from the previous two books in the series and has a much, much darker tone and subject matter. But if I'm being honest, this was probably my favorite in the series for those exact reasons. This book was such a heartfelt exploration ...more
5+ stars

“You’re a big deal—to me. You’re amazing—to me."

I was not expecting this. I didn't think The Heart Principle would hit so hard, but it really did. I wasn't ready for this book. I felt so overwhelmed while reading it, but my goodness... I loved it so much. I wouldn't be surprised if this ended up being my top read of 2021.

Anna Sun is a violinist who is struggling. After going viral in a YouTube video she's felt the pressure and it's building and building each and every da
Alexis Hall
**Sneakily obtained on NG from the UK publisher since the US publisher doesn’t countenance requests from plebs like me. Actually, I do feel legitimately guilty for having got this, since I requested because I wanted it, not because I thought I had any right to receive. And the imposter syndrome was so severe I thought about apologetically returning it but, well, I didn’t. Anyway, ARC received when it probably shouldn’t have been. Will buy on release**

Honestly, I think this is a fucking masterpie
5 stars! I loved it! I cried! Helen Hoang's best to date!

It's been a long wait for Quan's book, but it was worth it. I already love all of Hoang's characters, however this book felt so incredibly personal and so heart-filled, it go to be my favorite of hers.

After 5 years together, Anna's boyfriend suggests that they open up their relationship, so that they know they are not missing out on anything before they decide on the marriage. As he proceeds to immediately hook up with other people, Anna d
Sep 23, 2021 rated it really liked it
i thought this was a definite improvement from the previous book in the series!

i think its important to note that this isnt the most light-hearted of romance books. its tackles some very real-world problems when it comes to mental health, burnout, the pressure to make others happy, and familial duty/obligations. while i did experience some moments of intense frustration when it came to annas inability to say no/stand up for herself or her families degrading lack of compassion, i did find this to
Kelsey (munnyreads)
Aug 03, 2021 rated it it was amazing
Shelves: 2021-favorites
I’ll write an actual review when I’m not in the middle of the literal Grand Canyon, but I loved this.
✨ A ✨
So i'm just supposed to sit here and accept the fact that i dont have a Quan?
Cruel 😪

May 09, 2019 marked it as to-read
Shelves: put-down-for-now
Putting this aside for now.

The story is too bleak for my liking, my mood right now. Being in Anna’s head is exhausting. Her past trauma and current life are so grim and I can’t hack it. I want to give this book a fair shot since I’ve been looking forward to it, so I’ll be returning to it at some point.


Do I even need to say that this book needs to be about Quan? No.
But I will add my voice to the masses SO DEAR GOD PLEASE LET THIS BE ABOUT QUAN!
Arini ~ Miss Casually Reading
#1 The Kiss Quotient — 3.25 stars
#2 The Bride Test — 2.5 stars
#3 The Heart Principle — 2.25 stars


1. this was A W F U L . 😭

2. reading this was like opening a can of worms, and it left you traumatized.

3. when people say this is NOT a lighthearted romance, theyre entirely off base. first of all, i thought it meant this was the kind of heavy romance that would make me cry in blissful agony, but i didnt even shed a tear because i was too busy feeling ANGER and FRUSTRATION.

4. second of all, this I
myo (myonna reads)
when you’re most anticipated release becomes your most disappointing book of the year 😅

this was one of my anticipated releases of the year and i’m honestly so sad because i was disappointed by it. Quan was my favorite character in the trilogy and for his book to be my least favorite book hurts. i really don’t care for online dating as a romance trope because why would i read about that when i can just go experience it myself? i just expected something more fun and i did not get that.

but also the
I loved this book but holy shit, was this book sad. I was not expecting this book to be so incredibly sad and heavy and depressing, especially because the first two books in the series are pretty light-hearted and steamy and fun. So just a warning before you read it: this book is a lot, and it will probably make you cry a lot, and I wish I had known that going in because I was just wanting something light and fun and this book hurt to read.

I loved the romance between Anna and Quan, it was beaut
Larissa Cambusano
Mar 05, 2022 rated it it was amazing
i’m not even surprised honestly. ‘the kiss quotient’ & ‘the bride test’ were both 5 stars for me so this was a no brainer. i’ve been WAITING for Quan’s book and it did not disappoint. this one was so much deeper & more emotional than the rest and I loved that. I adored the conversations about therapy, diagnosis, autism, depression, and grief. I smiled, I swooned, I teared up.. I felt every emotion possible while reading this. Anna is an absolute angel and I fell in love with her, and Quan?? oh m ...more
destiny ♡⚔♡ [howling libraries]
#1 The Kiss Quotient ★★★★★
#2 The Bride Test ★★★★☆
#3 The Heart Principle ★★★★★

I'm terrified that if I slip, if I fail, everyone will stop loving me, and where will I be then?

Sometimes, a book is so bad, it's hard to give it a fair review. Other times, a book is so magnificent, it's hard to put my thoughts into words. And then, there are books like The Heart Principle, which hit me so deeply that, no matter how much I loved the book, it hurts too much to review until I've had time to process.

Oct 30, 2021 rated it it was amazing  ·  review of another edition
I’m absolutely in love with this book. It took me by surprise. I completely devoured it and did not expect it to deliver!

I laughed, I gasped and I cried. What else can you ask for.

It’s technically a lighthearted romance that also includes heavier topics such as mental health issues, rejection and grief. But it felt so realistic you know?

I always try to relate to book characters, I think we all do, in different ways. But Anna felt like I was reading about myself sometimes. Her musical burnout,
An intense, emotional and personal story/part memoir

Firstly I'd like to announce that even though I loved this, it wasn't the rom-com I was expecting after the first two books in the series. The synopsis on GR is also incorrect, as the book was rewritten and vastly changed direction.

Told in 1st person unlike The Kiss Quotient and The Bride Test, I would say this was more Anna's book that Quan's. Whilst Quan was amazing and dreamy in this, and had his own chapters, I felt that his journey and dem
Aug 10, 2021 rated it did not like it  ·  review of another edition
Shelves: botm
I hate giving Helen Hoang a one star review. I really do. I loved The Kiss Quotient and The Bride Test and have been looking forward to this book for months, but...it just doesn't work. It's not a romance. It's a contemporary fiction book about coming to terms with an autism diagnosis and battling mental illness. That would be great if it were a stand-alone, but it's not. It's the third in a romance series and that makes all the difference.

It's clear Hoang was working through some stuff when wri
Sep 12, 2019 marked it as to-read
Shelves: romance, poc, contemporary
Can you all believe this cover reveal just saved 2019?

1.) The Kiss Quotient ★★★★★
2.) The Bride Test ★★★★

Blog | Instagram | Twitter | Tumblr | Youtube | Twitch
in the author's note, hoang notes this book is half memoir.

to be honest, i wish it was 100% memoir, because not even 1% of it was romance.

review to come / 2ish stars?


i hated - okay, strongly disliked - the first book in this trilogy, and enjoyed the second.

how will i feel about the third?!

life is full of mystery and adventure.


reading books by asian authors for aapi month!

book 1: kim jiyoung, born 1982
book 2: siren queen
book 3: the heart principle
Jan 30, 2022 rated it really liked it
Shelves: gifted
i can't remember the last time i physically couldn't put a book down until i finished it but this book had me on a chokehold from chapter one and didn't let me BREATHE until i turned the last page 🚑 🚑 🚑 ...more
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Helen Hoang is that shy person who never talks. Until she does. And the worst things fly out of her mouth. She read her first romance novel in eighth grade and has been addicted ever since. In 2016, she was diagnosed with Autism Spectrum Disorder in line with what was previously known as Asperger’s Syndrome. Her journey inspired THE KISS QUOTIENT. She currently lives in San Diego, California with ...more

Other books in the series

The Kiss Quotient (3 books)
  • The Kiss Quotient (The Kiss Quotient, #1)
  • The Bride Test (The Kiss Quotient, #2)

Articles featuring this book

It's time for happily ever after! If you're looking for a story to pull at your heartstrings, satisfy your soul, and make you believe in true...
599 likes · 80 comments
“No one should need a diagnosis in order to be compassionate to themself.” 51 likes
“I do wonder if she’s acting just like I am. How much of what people say is genuine and how much is politeness? Is anyone really living their life or are we all reading lines from a giant script written by other people?” 35 likes
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