He reads so much detective stories that he now can see which act is a fake. He's been observing you for a few days, and he knows how you are always unavaiable on night because you have missions, how you are cold and sarcastic to people when you are not at school, how your innocent and kind act is just... well, an act. But he doesn't have proofs, so he can't really do anything. But he knows your secret. You're too kind to be really kind.