I'm sorry but i think the mc is kinda stupid
she's pretty much supposed to be, nanakusa is literally listening to someone say "you're not actually special to her she treated you exactly how she treated me" by a person who flat out said what happened to her and thinking "i'm special to her" right after. it's not the most unrealistic thing because it def happens often irl with "no way i think she really likes me" thing people do but you do have to suspend your disbelief a bit when you're just a person reading a mangaI'm sorry but i think the mc is kinda stupid