The only way FM is going to win is on points.
But you forget one thing, CM started with boxing, he is a champion in the best division in MMA, he was a champion in different MMA sports, he has beaten BJJ champions, karate champions, Wrestler champions, he is the better all-round fighter.
Were he to fight a young FM he would have no chance but as it stands now, CM is a skilled and smart fighter, he is more motivated, he has better reach, is taller, is stronger, faster and moves very orthodox. Standing he has never been defeated. have you ever seen how Jose Aldo fought in the past? This guy was a beast! 10 years the champ! KO'ed in 13 seconds..
FM is only in for the money, is older, slower, less power and motivated for the wrong reasons. Now am I saying like a lot of people that CM will KO FM in the first rounds, I highly doubt it but CM has more chance in the boxing ring than FM in the octagon.
But, FM is probably going to win, even though he said he will move forward this time but we all know he is just talk, he might do it at the start and after eating a couple punches from CM he probably is going to say fuck it and will fight like he always does, on the defense out-boxing his opponent on points.