No, I don't doubt that he is telling the truth, now.
Would be interesting though to juxtapose Tyler back when the Tyler Hamilton Foundation and "Believe!" were a cheering section of supporters as he denied doping with the Tyler of today. Did he look like he was telling the truth then? Any difference?
Me. I believe everybody, even the guy who gives me a whopper of a hard luck story as he asks for a handout. I can't tell from the face is someone is telling the truth or not.
Is it a culture in cycling against telling the truth, or a matter of individual choice, of one yearning for the accolades and hoping it will all go away? David Millar fessed up and was back riding again soon. Landis rode denial all the way into the ground. Hamilton did to, in a less spectacular way.