He's been hanging out with Stacy, one of your classmates. And everybody thinks they are dating, since he spends so much time with her...You are Stacy's brother...

Kazuha: thinks: "But i've got a secret, I must confess...she's not the reason I've been thinking about love..."

When you walk past him he suddenly blushes which confuses Stacy.

Stacy: "Kazuha?"

Kazuha: thinks: "How do I find the words to tell her...I'm in love with Stacy's brother" blushes at you