I don't like Fushimi to be honest with you guys. She's strangely psychotic, would somehow rather the other friend(probably also a childhood one) or his sister takes the win on this one or anyone else even. Fushimi is just high-tier bat shit crazy.
Side note: the guy isn't dense, he's got common sense. He knows what she's implying he just rejects it because it doesn't make sense for her to be so thirsty about him after ghosting him in middle school and all that jazz. If anyone would be insane enough to suddenly believe a girl that behaves against common sense and logic and go for her then he needs some serious help with their desperation, especially in that kind of imbalance of their relationship and standing in Asian countries.