When you're unashamed, you're proud or bold. If you're an unashamed cat lover, you're more than happy to show your friends the hundreds of photos of your cat on your phone.
To be unashamed is to act in a completely open way, without any embarrassment or shame. You should be unashamed about your love for soap operas, even if your friends think they're silly: you find them fun and relaxing after a long day at school. Unashamed adds the "not" prefix un- to ashamed, "feeling shame."