Don't you think that maybe trash talking is just part of the game to make these stuff more appealing to the masses? Maybe it worked back in the old days, when it was new, but do you think fighters now pay any attention to this stuff?
Conor has an enormous confidence and self-belief and he genuinely believes he is going to win.
Again, I might just be a tad too cynical, but this just reminds me of how every time an artist releases an album, it's always their "best album to date". Given how much marketing is a part of everything today, I'd think it's part of boxing and MMA too. What is a fighter supposed to say? "I think I have a slightly above-average chance of winning the fight"? At any rate, being positive is a core part of being prepared psychologically for the fights, so they must believe they're going to win.
RE: Floyd Mayweather vs. Conor McGregor