You don’t, unless you want to be prepared for violence. Read the news today. The world is not becoming safer. Hope is a terrible strategy, and luck is terrible tactics.
If you had a professional protection detail, you might not feel very safe if you thought they had zero training.
Now consider that you are your own protection detail. You are your own first responder. You are responsible for your own safety and defense, and that of your family.
Why do you need self-defense training?