How does Sam Know?

[LadyBrooke]

I think Boromir's need for forgiveness is bound to his nature. Faramir exhibits the type of behavior we all wish we would when faced with the ring (in the book), but Boromir doesn't.

Boromir thinks like a commander of Gondor's army would have to think - that any weapon should be used against the enemy - but he is a just, honorable man. His need for forgiveness comes after the ring has left and he can see what it has cost and what it might cost. While we know that everything turns out all right, there was no reason for Boromir to think that two little hobbits could find their way into Moria and destroy the ring by thereselves. He might not only have failed himself but doomed the whole of Middle Earth. Also even if no oath was laid upon them, Boromir may still have considered it his duty to protect the company, for what has he been doing his whole life but protecting other people as a soldier.