From Cross Infinite World:
Jill is sentenced to death by the crown prince, her fiancé. But just before she dies, she’s sent back in time six years to the party where their engagement had been decided. To avoid this route of ruin, Jill immediately proposes to the person standing behind her but it’s the man who was her greatest enemy, Emperor Hadis. Jill knows all about his future descent into evil. She quickly retracts the proposal but the delighted Hadis takes her back to his castle and makes her a meal. Completely won over by the food, Jill makes a life-changing decision.
“I’m going to reform. No, I’m going to make you happy!” It’s time to redo this life with the enemy!