Daughter of No One by Sam Ledel

Princess Aurelia's dreams of a life full of love and adventure become even more alluring when she meets village outcast Jastyn. Aurelia refuses to deny her attraction even after an unexpected attack on her family catapults her into the center of the Kingdom of Venostes's sinister intrigues.

Jastyn Cipher despises the royal family. After all, they are responsible for the exile of her mother and their life at the bottom of the social rung. She refuses to acknowledge her attraction to Princess Aurelia even when she is forced to seek help from the royal family when her sister falls gravely ill.

While the circumstances of birth might keep them apart, fate seems determined to bring them together. When Aurelia is kidnapped, she and Jastyn must face their enemies, fae and human, if they want to survive.