What you think about yourself will always surface. It is a self-fulfilling prophecy. Our brains are so amazing that they help us make our thoughts reality by changing our behaviors to that out come. So if you want to achieve success you need to think you will. Anyone can do it, you just need to believe you can!
This is a example of self-fulfilling prophecy; in which inaccurate expectations lead to actions that cause those expectations to come true, which this picture with a quote telling us that if we have or expect anything with confidence, becomes our own self-fulfilling prophecy.