YA Fantasy. Read from 2012-2016. I think mc suddenly gained the ability to see fae-like/fantasy creatures. She might have had a power related to being able to understand and speak with these creatures. I think the title was one word.

[Aster]

Spoilers ahead.





I have a poor memory so I apologize for the lack of details. There is one very specific scene that I am remembering where, as a result of being in proximity of these fantasy creatures (and working with them or having some kind of deal, maybe?), she started becoming more like them and eventually lost the ability to tell a lie. So, she started figuring out how to speak in loopholes. Someone asked her how she was doing, and she was not able to lie and say "I'm fine" or "I'm well", but she exploited the loophole of instead saying "I'm good", as her reasoning was that she believed that she is a good person morally.

[Valeria]

Tithe or Valiant by Holly Black perhaps?