[She means it. He knows that she means it, however impossible it is to hold on to someone forever, because this happened in a dream once. Chuck hadn't let go then even though she'd had no reason not to.
Nathan loves her for that. He doesn't know how to articulate it, but it's true. No one--not even his mother--has ever been so unafraid or unnecessarily kind. Chuck has no obligation to care about him. She has no reason at all to want him to be okay, and the fact that she does anyway is simultaneously wonderful and terrible because he hasn't done anything to warrant that kind of treatment.]
Thank you. [And maybe it's okay to cry a little. She won't think less of him for it.]