There was a girl whose sweetheart kept a secret from her.
She also tried very hard to pretend not to know.
Her sweetheart said: "Our Ayou must marry the person who is most worthy of her in the world. This person can be you or him, but it cannot be me."
The girl said seriously: "Then I, I will kill you and him."
The sweetheart clutched her cramped chest and felt pitifully aggrieved: "Ayou, you have changed, you have become bad. Who taught you these things?"
The male protagonist is domineering and childish, and the female protagonist is a genius with a slight stutter.