How we cite our quotes: All quotations are from Harry Potter and the Prisoner of Azkaban.
Quote #4
SIRIUS: I would have died! I would have died rather than betray my friends!
Sirius lets his true nature show here, and he continues to prove it throughout the series. He'll risk himself to save Harry more than once.
Quote #5
HARRY: Well I just didn't think my dad would have wanted his best friends to become killers. Besides, dead, the truth dies with him. Alive, you're free.
Harry repays Sirius's loyalty by giving him peace of mind. And it proves to Sirius that Harry believes him, and will now be loyal to him too.
Quote #6
SIRIUS: I don't know if you know, Harry but when you were born, James and Lily made me your godfather. […] I can understand if you choose to stay with your aunt and uncle but if you ever wanted a different home...
Sirius attempts to earn Harry's trust and loyalty by offering to be a father figure of sorts to Harry. However, the movie doesn't really address the fact that Sirius takes back this promise at the end. Does Harry feel betrayed when Sirius tells him no, he can't actually live with him yet?