Quote 1
"Naturally I don't believe books and I don't believe teachers. […] but I do believe—it's important after all for me to believe you. Christ, I've got to believe you, at least. I know you better than anybody" (11.84).
Oh, irony. Or is it? DOES Finny, maybe, in some way, know Gene better than everyone else? After all, he does perhaps at some level know that Gene caused the accident and why…
Quote 2
"What I mean is, I love winter, and when you really love something, then it loves you back, in whatever way it has to love." I didn't think that this was true, […] but it was like every other thought and belief of Finny's: it should have been true. So I didn't argue (8.59).
Look at Gene's reaction to this notion: it should have been true. He's enticed by Finny because he's enticed by the world Finny has created – a world of youth and peace.
Quote 3
"It's you, pal," Finny said to me at last, "just you and me." He and I started back across the fields, preceding the others like two seigneurs.
We were the best of friends at that moment (1.38-9).
From the start, Gene's friendship with Finny isolates them from others.