The 44-year-old Ultimate Fighting Club president made the claim earlier this week at the UFC 173 Ultimate Media Day. Rousey is the current women's MMA bantamweight champion, while Mayweather is professional boxing's undefeated welterweight star.
The fight would most likely never be sanctioned by a commission, but fans and professionals continue to speculate about the hypothetical match. Rousey herself has said she could take on the boxer, a sentiment White echoed during the media event Thursday.
"Listen, I get it," he began. "It's hard for guys to wrap their brains around that one. Ronda wouldn't beat him. She'd hurt him badly."
White said he believes Mayweather would dominate a boxing match, but is confident Rousey would win in an MMA fight.
"She'll kick the living [expletive] out of me," he continues. "And you. And everybody else standing here, whether you like it or not."
Rousey is currently in Cannes to promote her first movie, Expendables 3. She is scheduled to fight Alexis Davis at UFC 175 on July 5.