Sasha is extremely smart

It's time to get back into action and go into Yuushe's route of Tsuki ni Yorisou Otome no Sahou! Sasha already knowing (since the very first day they met) that the protagonist was actually a male was kind of hilarious. Asahi tried so hard to hide his identity and yet it was plain visible to one of the characters.
Of course Yuushe was completely oblivious to the whole thing, but I don't think any of the girls actually suspected anything until much later in the story. Though in their defenses, Asahi looks like a perfect girl, I would've been fooled too.