Sorahana
Oh boy the reincarnator messed up big time ... this was the wrong way to mess with MC ... not really sure how much she knows about MC's circumstances but pretty sure MC helping her brother would be a key detail so all you need to some how switch MC's notes with a fake one that will make the brother fail and then naturally the brother and the mother will punish her ... or even better invite a bunch of high standing female secretly and intrude on their sparring session cause I the females who know martial arts are looked upon in positive light and pretty sure it would be even worse for the brother