Tempting Raven by Jessica Sorensen

Eighteen-year-old Raven was just an ordinary vampire until Fate chose her as the new vampire queen. And Fate has a twisted sense of humor because it chose Rhyland Midnitegale as king, who just happens to be her sworn enemy.
Raven isn’t thrilled about ruling with Rhyland, but if she doesn’t step up to her title, the chaos, rebellions, and murders taking over the vampire world will only continue to get worse. So she accepts the position, but secretly hopes that maybe Fate will change its mind.

She soon learns that being queen comes with many rules. Rules that bind her heart and soul to Rhyland in ways she never imagined. Rules that keep her life out of danger from outside threats. Rules that she must follow or the entire vampire kingdom pays the price.
But dangers may be lurking close by, and Raven may be cursed with more than just the title of the queen.