[Sweet first, then cruel] As for the knife part, emmm, I'm not sure whether the knife will cut into your heart or not. It's up to you.
"My little sun, give me a chance to love you in the next life."
"You are my only morning star."
The heroine and the hero were neighbors when they were young, but the heroine didn't know him. The hero had vague feelings for her. Later, the heroine moved and met in a high school not long after that. The two had a crush on each other. The heroine later got cancer. Faced with his confession, the heroine refused and died! Then the male protagonist went to the lake they often went to and died! (It's a bit bloody... Accept whatever you accept)
Intention: unclear