It is not what we say or think that defines us, but what we do.
Jane Austen.
What we do is what others see and how they define us. What we think usually makes up how we define ourselves. The trick is to have the courage of your convictions and have your actions reflect your beliefs and thoughts. Then the two coincide. If you don't, then understanding that lack can at least help you reconcile how you are seen by others and how you see yourself.