Its pretty obvious what he's trying to do. He wants out of a relationship made of pity, and he's trying to throw away his feelings. By confessing to her and her turning him down, she'll feel too awkward to talk and hang out with him anymore, because the fact that he likes her is out in the open now. And a public confession is also effective, because if she continues to hang out with him, more rumors will spread. He's basically on a pedestal screaming out loud "I LOVE SUNGAH," which will then in turn keep her away from him even more, to likely single sentence interactions. He wants to push Sungah away from him by making an air of awkwardness around them.
But it's pretty clear what's gonna happen. He's expected her to turn him down, because there is literally no reason for her to accept his confession. BUT, judging by the next chapter title, she's probably going to accept. For two reasons. Pity, which is unlikely, OR, she sees resemblances from him to the RanChat guy (who are the same person), and are going to connect those two to try to fix these confused feelings of hers, because she doesn't know that the MC and the RanChat guy are the same people.