Blood kiss - J. R. Ward

Paradise, blooded daughter of the king's First Advisor, is ready to break free from the restrictive life of an aristocratic female. Her strategy? Join the Black Dagger Brotherhood's training center program and learn to fight for herself, think for herself...be herself. It's a good plan, until everything goes wrong. The schooling is unfathomably difficult, the other recruits feel more like enemies than allies, and it's very clear that the Brother in charge, Butch O'Neal, a.k.a. the Dhestroyer, is having serious problems in his own life.

And that's before she falls in love with a fellow classmate. Craeg, a common civilian, is nothing her father would ever want for her, but everything she could ask for in a male. As an act of violence threatens to tear apart the entire program, and the erotic pull between them grows irresistible, Paradise is tested in ways she never anticipated--and left wondering whether she's strong enough to claim her own power...on the field, and off.