During their last night together, what does Sam encourage Charlie to do?

In Chapter Four, Sam unveils her Christmas gift to Charlie, which is an old typewriter. On the paper, she types, "Write about me sometime," and Charlie types back, "I will" (165).

Sam asks Charlie to find out what he really wants and find what his happiness is, not the kind of happiness that people want you to have, the one comes from his honest feeling. I guess it also means she wants him to be who he really is, to find his best self.