Rockmyheart: Why did Iorveth let Roche live in that duel? Better the devil you know? Out of respect? Or just knowing that he can beat him?
Why is this posted as a question? The answers are subjective, so you really can't choose a post as the "right" post. Just wondering.
And I'd bet it was partially because killing someone in a duel is almost a sign of honor, and letting him live knowing that he lost in a straight-up fight is worse than losing. With a rivalry like that between them, it's so much sweeter to force the other to live the rest of their life knowing that you're better.