I just read a spoiler and based on previous info, I can assume that Charlotte is a bitch. However, she is smart. She knows that the mc is highly valued by Dietrich, and that she belongs to the noble family. So by shifting that guy's attention to MC, the family can get involved and deal with the guy instead. Although she won't get away free because Dietrich will come for her ass, at least she won't be sold. don;t get me won, still a bitch, but a smart bitch
https://sleepytranslations.com/series/how-to-protect-the-heroines-older-brother/chapter-35/
the chapter next chapter isn't posted on mangago, but I found it on the scanlation groups' website.
From what I heard, this (35) is the last chapter of season 1, and that the author will be taking a hiatus dude to their health.
(づ ̄ ³ ̄)づ
ヾ(❀╹◡╹)ノ~
ε=ε=(ノ≧∇≦)ノ