I Lost The Leash Of The Yandere Male Lead

I transmigrated into a novel and became the villainess, Serina who comes from the noble Ducal Melford family.  As a well-to-do character, I tried to mind my own business, but the story had other ideas. A self-proclaimed mother brought back a boy – the duke’s heir and a genius wizard -intent on brainwashing and blackening him.  The contents of brainwashing are two things: 1. Obey our family. 2. And fall in love with Serina.  Thanks to that, the brainwashed twisted yandere is obsessed with me… I can’t do this. I have to undo the twisted character’s brainwashing! By the way, what’s this situation?  “Now that the brainwashing is gone, I’ll do as I please. So Serina, please, let’s do our best.”  I’ve solved his brainwashing… but why does he seem even crazier than before— Did I make a mistake?