"what do you take me for?"
IDK, a girl MC tried to help out then ended up having passionless sex with. Was told never to meet again and then become family and you try to get in for seconds.
oh and now we have Chekov's hitman. WTF did she get into? did she break off with a mobster last chapter?
"I'm always misunderstood"
We aren't mind readers and I just described the entire extent this dude knows you (oh you're also classmates). Secrets are fine but don't act like MC should be in the loop. You realized he only slept with you because the alternative was probably Ugly Bastard #2 right?
"I thought you weren't interested"
uhh, yea. Nevermind the step sister dynamic. That sort of happens when you reject a guy who confesses with you. Well, reject a not creeper guy.
and (some) women wonder why men don't like playing games. Just tell him what you want.