It really comes down the Element of Surprise and First Strike. If the attacker had been aggressively violent, the girl may not stand a chance. But bravo, she is brave, and did not react like what most girls would.
not necessarily. physical strength plays a small role in martial arts. the right technique will more often than not get you through with little effort at all. We are always thought that if you are using strength to break out of grabs and holds, you're doing it wrong.
notice how she grabbed the guy's arm by the wrist and elbow? that basically gives her control of the arm and she can pretty much do anything she wants with it, and his body will have no choice but to follow.
besides, to think that he can take advantage of the girl because she would be weaker than him is a silly assumption, especially when she's in her black belt uniform.
seriously, who in the right mind will want to mess with a black blet when one can see the "victim" in their dojo uniform? think that guy has got no IQ & EQ & SA.