This is an AMAZING discussion. I would have never thought that Fredo had different intentions than those he signaled in the boat house to Mike. But...after Fredo tells Mike that he didn't know it was going to be a hit, Mike asks him...you believed that story? Fredo's reaction is... they said there was somethin' in it for me. I sense that this suggests that Fredo's logic about the hit on Mike was clouded by his own greed.

However...I do not think that Fredo would have done it again.

Granted...he might have slipped up again had Mike not killed him. But...Mike sure killed him.

He told Mike that he didn't know it was going to be a hit. I "believe" him.