I suspect you're overestimating your own abilities (as most people who do any kind of martial art tend to think they're tougher than they really are) and/or underestimating the force and violence applied during a rape. Is your BJJ really going to do you any good with the weight of a 200lbs+ man pinning you down, grabbing the back of your head and slamming your face off the floor?
Yes. If you’re fending off a rapist (Or any attacker) you don’t have to “win” the fight, you only have to convince them that it isn’t worth the effort. If women were willing to get the shit beaten out of them (Because a great majority of women would obviously lose a fight with a great majority of men,) most rapes would be prevented either do to the amount of noise being made, evidence being created or the guy just giving up because he’s had too long to think about the crime he’s committing. You don’t have to kick the guy’s head off, you just have to let him know that he’s really going to have to work for it.
That said, regardless of if they want to admit, most women would probably prefer the rape than the beating, but I suppose that’s why physical intimidation works
This guy has absolutely no idea how deadly jiu jitsu is, whether it’s Japanese or Brazilian. If she’s anywhere near brown belt, she can beat any guy any size who’s untrained in grappling martial arts.
All bets are off if he has good training too, then strength will matter. But most men who do these martial arts and are good at it don’t need to rape, it keeps them so fit and confident women flock to them.