Psychopath who corrupts an innocent girl.

[madarahyuuga]

Good evening everyone, a long time ago I read a very good story in which a psychopath made a bet with a friend that he could turn a girl (I think she was a librarian) into a bitch. In the story he creates several plans to achieve this and makes her repeat several times several phrases like that she loves him, that she was a bitch, that she belonged to him and stuff. This was for her to begin to assimilate such phrases and start to believe in it.

And in the middle of the way he starts prostituting her, selling her, sharing her with several friends and stuff.

Does anyone know what story this is?