They are lying in bed together. He says,

“I will always love you even in next life. I will find you no matter what.”

She says, “How would you know someone you love in next life is me?”

“I just know. If I love someone, then it is you.”

“What? What if you love someone else, and tell me later you thought it was me?”

“No, I will know it is you because I won’t be able to love anyone else but you.”