It might seem preposterous to believe Emma Watson is the new Arnold Schwarzenegger just because they were both Hollywood's best paid actors and you would be right. Emma Watson is not the new Arnold Schwarzenegger.
But Arnold Schwarzenegger will forever be remembered as the old EMMA FUCKIN' WATSON!
For you people lacking imagination: you can figuratively "kick someone's ass" by convincing them they had been wrong, or by winning in Checkers or Bohnanza or Darts or electronic sports or whatever, or alternatively by enlightening someone.
(That put aside, I don't rule out that Emma Watson is a good mixed martial arts fighter despite appearances to the contrary. Do note that while she might get angry (which has been erroneously referred to as "verbal violence"), she won't attack you out of the blue or even deliberately kick a friendly cat or dog.)