Fantasy about a girl who steals a dagger from a powerful fae and then is forced to help him with their females fertility issues

[Taylor]

Spoilers ahead....

This book is about a girl who works for a guild or something similar and under the direction of her demon boss, is to steal a dagger (or similar artifact) from a powerful fae/elf. While doing so, she catches his attention. We learn throughout the course of the book, that the girl is actually his mate, and she is actually a fae/elf (the only pure untainted elf). She was hiding as a human but is actually an elf/fae. She was originally a human mother in a different world, but then she was summoned to this world where she was transformed into an elf. Stuck on this world she hid as a human. We also learn that she has been hiding from her mate for several hundred years. Also, she is a healer and the only fae/elf female not plagued by their fertility issue due to her being summoned and transformed. Through the rest of the book she works with the fae to solve their fertility issues and resolve her mate status with the powerful fae/elf.

I believe I read this book around 2010-2020 (but cannot be sure).

[Melanie]

I'm not sure if this is it but here's my guess: Mark of Truth (this is the newer cover by the way)

[Taylor]

Hm, that book isn’t the right one, but thanks for posting this. Something I can definitely read in the meantime.