There are no guarantees in self defense but there are a few almost guarantees that I can give you
1)If you learn from Sean Stark I can almost guarantee that you will learn some important indicators of danger.
2)If you pay attention and practice, I can almost guarantee you will hit harder. (A lot harder).
3)If you pay attention and practice you will be able to take those hard hits and land them with accuracy on damaging targets.
4)If you pay attention and practice, I can almost guarantee you will become mobile, agile and overall a harder target to hit.
5)Finally I can almost guarantee, you will feel like you are part of something important, something that makes the world a better place.
Mind you before you see any of that, I guarantee you will need to get off the couch.