A man with integrity will always be attractive to women. Knowing who you are and being willing to stand up for what's right is incredibly sexy and it's a sign that you'll also be honest, faithful, and reliable in a relationship. Guys with integrity generally only work jobs that are ethical and in line with their life philosophy. You won't catch them working for casinos or huge oil companies.
Integrity isn't really something that can be taught - it comes from within yourself. However, you can start to become more aware of what's going on around you and start developing some principles. What do you care about? What do you stand for? What things are more important than money to you? Figuring out what you truly care about will lead you to integrity. This is something women can really respect in a man.