Honestly, Nanase is kind of awesome. He loves Hana, but he also knows Hana doesn't love him. But he tells her anyway, in a very similar manner to how Hana tells Shiori. Hana doesn't tell Shiori because she expects it to work out, she tells Shiori because she doesn't want to deny her feelings. And that's the exact same reason that Nanase tells Hana he loves her. Well, that and to motivate her to do the same thing he's doing. There's not many guys in yuri stories, and even less that are good, but he's one of, like, two good ones I can recall.