The Pureblood Daughter by Emberly Wyndham

A mysterious viscount and a well-kept secret will change Adelina’s life forever.

Adelina Gray is destined to be a spinster; it’s been years since her debut into society, but she’s yet to land a match. Until the rich and powerful Viscount Rosetti sets eyes on her.
The power of his gaze makes her swoon—literally—and when he comes to call on her the following day, she wonders if she hit her head a bit too hard on the ballroom floor. The viscount seems intrigued by her, though she doesn’t know why, and he doesn’t give up his secrets easily.
Despite her father’s fervent disapproval, Adelina allows the viscount to court her secretly, and he leads her down a dark path of mystery, lust, and blood. He unlocks something within her she never knew existed, and now that it’s been freed, her life will never be the same.