Tsuna just didn't want to insult Gokudera and make him mad.
"It's not an excuse!" Tsuna replied, sitting up abruptly. "I just accept the fact that I'm not very good at everything I try. It doesn't mean I wont...I mean...s-someday I'll be with someone who, who really loves me and so, so they won't care. A-and they'll be patient!" Yeah, Tsuna had turned really red, feeling kind of embarrassed, but that's what he believed.
"So that's how it'll be!" he took a pillow and put it on Gokudera's face so that he didn't have to look at it anymore.