His Violent Vow by Winter Sloane

Mafia princess Katherine ‘Kat’ Marino doesn’t have a choice. Promised to her father’s enemy, Kat agrees to marry Angelo Vitale because duty compels her. All she has to do is pretend to be Angelo’s obedient wife. Liking the vicious monster in the expensive suit had never part of the plan. But Angelo’s possessive touch sets her skin on fire and his ardent kisses leave her wanting more. When the line between hate and love blurs, can Kat surrender her heart to a savage king?
A business arrangement—that was all Kat amounted to. Fragile and boring are not the words Angelo would use to describe his new bride. She’s feisty and passionate, a queen capable of bringing a ruthless killer like Angelo to his knees. If he’s not careful, Kat might slip past his guards and own his tainted heart.