Bound by Honor (Born in Blood Mafia Chronicles) by Cora Reilly

beauty. What many consider a gift means her doom when she’s forced to marry Luca Vitiello to bring peace between two mafia dynasties. Luca is the future Capo of the New York Famiglia, a man known for his brutality—and for crushing his cousin’s throat with his bare hands.
Aria is terrified of marrying a monster like him. He may be one of the most sought-after bachelors in New York, thanks to his good looks, wealth and predator-like charisma. But Aria knows the bad boy aura isn’t just a game; blood and death lurk beneath Luca’s striking gray eyes and arrogant smile.
In her world a handsome exterior often hides the monster within; a monster who can just as easily kill as kiss you.
Yet, there’s no escaping the arranged bond, much less a man like Luca. He’d follow her to the end of the world.
Her only chance to survive in a marriage with Luca is to gain his affection and work her way into his heart—even when rumor has it that Luca doesn’t have a heart to begin with.

A mafia princess known for her beauty given to a monstrous man.