In this era it's easier to differentiate this difference, everybody knows wrestling is entertainment and MMA wouldn't be and it would be sanctioned and ran as a sport, with independent commission. It would be easy sell if made clear, and you see the fights being real. It's a small issue at start but 1 that could be quickly overcome with strong clear rhetoric and then genuine action played out. At the end of the day he's a buisnessman, MMA is just another sport like XFL is, if XFL isn't fixed no need the MMA should be.
A fight requires 1 person agree to lose to fix it, only the promoter and the losing fighter need to be in on it, a football game is less fixable. Plus MMA fans would not go for it, they generally hate any association with pro wrestling.