(Couldn't decide between that one and this one)

(And kicking things [safely! in class!] is great stress relief)

There is no one magical thing to learn to make you "safe" in the face of an aggressive force. But cultivating the practice of self defense in all its forms, including cultivating inner strength and calm, doesn't make anything worse.

These things are cultivated through practice of the martial arts, not just learning a particular move or kick or block. The regular practice builds confidence, spacial and situational awareness, and inner strength in a way that is difficult to describe, but easy to feel when you're in it.