I've personally found working out to be the magic pill in this respect. Sure there are muscular men who are pussies, but it's WAY easier to be strong and confident when you are in shape. I also think that martial arts is a great way to build up inner confidence. I personally did muay-thai kickboxing. Make sure that whatever marital arts you are doing, you are doing lots of sparing and make sure there is at least a potential to get hurt. This is why I like boxing. This will also help you find some good mentors.
As stated in "The way of the superior man", she wants the killer in you. Don't be afraid to act on what you think is right. Don't be afraid to feel emotion deeply. The concepts of honor and integrity are what I personally think makes a true man. Do what is right no matter what. Live your life like it matters.