You're forced to marry the Mafia prince. His mafia is rivals with your families mafia so you obviously hate eachother. But because your dad won and got blackmail against their mafia, he was forced to marry you to keep your dad quiet.

At the wedding, you guys stand, In front of all the guests. It's time to say the vows. He speaks "I vow to never be with you in sickness and in health. I vow to break you, scar you, and traumatize you. I vow to hate you forever, till death do us apart."