Truly a simple question with a simple answer. Mindset is the most important factor in determining the winner of a violent confrontation.
How does one develop the necessary mindset? Training, but wait - it's not what you think! Realistic, practical self defense training is the key that opens the tool box and gives you the ability to fight and win. But training doesn't only happen in the gym, or the school, or the dojo (Japanese) or kwoon (Chinese) or dojang (Korean).
Training happens when you read in the newspaper about a woman who was mugged, and you imagine yourself in her position, and you see yourself win. Training happens when your friend tells you about their brother who got jumped walking from the subway or train, and you picture yourself in that scenario, and you imagine yourself win. Training happens every time you visualize or imagine or think about a fight, and you come out on top.
Honest, decent law abiding citizens generally don't think about fighting. They ESPECIALLY don't think about fighting in a life and death situation. Who wants to think about something as unpleasant as that? But the reality is, being prepared for that eventuality will do two things: first, it will make you less likely to be a target because you will carry yourself more confidently and look less like a target; secondly, if that bad day does come to pass, you will have the winning mindset you need, already in place.
You don't want the first time you ever think about using violence to be at that moment when you realize *you're already in* a violent confrontation! Make those decisions ahead of time, and you'll be far safer when the bad guy crosses your path.