White stated on a potential matchup between the UFC women's bantamweight champion and the undefeated championship boxer, "You take a street fight, Ronda wins that fight and hurts him badly. You do an MMA fight, same result. Boxing match, Floyd Mayweather chews her up."
Obviously Dana White is an MMA promoter and is trying to pump up his huge women's MMA superstar in Rousey. However, this debate is absolutely ridiculous, since such a fight will never happen and it's a silly thing to bring up. Any type of sanctioned fight between Mayweather and Rousey would never take place. They wouldn't throw down in a street fight either. However, it makes for getting fired up comments from White at press conferences, hence why it continues to be brought up over and over.
USA Today Sports/MMAjunkie released an extended clip from the scrum at the above link.