My bet is she got kidnapped, and the teacher being evil is a red herring. It might be more interesting if her trauma came from witnessing the teacher killing her kidnapper.
Hey, it took a while but I found the chapter. It was chapter 118 where Naddy starts speaking like a normal person. Meme says she has a little sister who plays basketball.
The brother could offer Conia the entire kingdom to rule and she'd just say, "Don't wanna." and then go roll around on the floor. He should give up whatever his plans are before they even begin.