On the day she died in the ward, no one came to see her.
He broke in with a knife, fell on her, and said "I'm sorry."
She hated him for five years. At the moment she died, she realized that he loved her more than she imagined.
Reborn five years ago, she found that she owed him a life. The system forced her to repay her debt, and a life-and-death contract bound the two of them - even if he died, she wouldn't survive more than three days.
She doesn't run away anymore. In this life, she will protect him.