Looking down at Peter's hand atop his, Nathan was silent, his expression that stoic set the lines of his face were all too familiar with, and then finally he looked up again, searching Peter's face. He wasn't looking for the ability to believe his brother, as that was there, but for the faith to do it despite every logical, sensible objection there was to the idea of all of this. Logic and fear had hampered him in the past, but he couldn't let it now, there was more riding on this moment than just accepting the existence of the things that went bump in the night. This Peter had lost someone to believe in him, and Nathan wasn't going to do it to him twice.
"I believe you," he said quietly, holding Peter's gaze for a moment so Peter could see, could know, he meant it. He shook his head slowly. "Vampires." His expression was apologetic, because believing Peter was one thing, but accepting , not just the vampires but that there was a whole host of things in this world likely to test formerly-held convictions, was taking just a bit longer. "This is just- a lot, Pete." And he knew Peter knew that, but he didn't want Peter to feel this had anything to do with his faith in him.