It's hard to do, but to be true to your foundational beliefs, the essence of who you are, is important. It's especially hard when the person you are isn't the same (or even close to the same) as everyone else. It's a challenge not to go on the defense or the offense when other people misunderstand, or even mock and attack the fundamental core of your being. Being true to yourself and allowing the external things to fly past without a reaction from you is almost impossible. But that is true confidence.
Don't be mistaken in what I mean, however. Being true to yourself doesn't mean you have the right to force your beliefs and opinions on others. The same confidence that allows you to be true to you requires you to be harmless to others and to understand that each person comes from a different place. You must allow for perspectives other than your own. Perspective in art is a great example... Depending on where the artist stands in the room, the outcome of the piece of art changes.
The important thing in all of this being true is not to attack or hate each other. Respect others, listen to others, consider others, and do to others what you would want them to do to you. Humility is essential to true confidence.