I can see it now; Hana will tell someone else that she she saw Chang-wook confessing to a guy and a rumor will circulate around the school that he's gay. Of course Chang-wook won't tell her the truth (neither that he's not gay nor that he was practicing confessing to her) so she'll give up on him and pursue some other guy leaving Chang-wook even more depressed and dejected.
Of course, this whole situation could have been avoided if Hana had just been upfront with Chang-wook and confessed to him instead of that stupid-assed trying to act nonchalant about finding out if he was interested in her first. Ugh! This is going to be very annoying for who knows how many chapters...