Oh Manwe....you're just...too nice to understand! xD In all seriousness though, I bet it was difficult for Manwe when Melkor asked for pardon. Part of him would distrust Melkor, yet part of him would long for his brother to be telling the truth and sincerely wanting to make amends. Tolkien also wrote that since Manwe was free from evil that he could not comprehend it.
Ulmo by Wavesheep.deviantart.com. Lord of Waters. Unlike the other Valar, he was not married and had no fixed dwelling place. He lived in the deep waters of the ocean, and seldom troubled to come to Middle-earth unless the need was dire. Ulmo was one of the chief architects of Arda. In power he was second to Manwë.