I think that, before the shooting, Roth really had Michael conned into thinking that Michael could take over Roth's empire without violence--and that Roth would simply fade away to a retirement of playing shuffleboard and pinochle with all the other Florida geezers.
Yeah when Ola tells Michael "our friend in Miami will go along with.." - Michael looks like he believes it... but what was really going on in his head?
He just believed it because he wanted to believe it. He gave Johnny a fervently grateful look, clasped his knee and said, "You tell him that's greatly appreciated"--a rare show of emotion for Michael.
Yeah I think you nailed it... "he wanted to believe it"... just like he wanted to believe Fredo wasnt involved... only hearing Fredo blab at party could he no longer "want to believe"
"What I want.... whats most important to me... is that I have a guarantee" - Train approaches.... Bang! Bang! Bang!
