Dance or martial art?

Neither one of these builds character (or maybe either of these will, read on). You build character by working hard through difficulties to achieve something of value.

I guess dance, or martial arts could do this if you gave your full self to it and accomplished something important to you.

But, if building character is your goal, you might think about voluteering your time with Big Brothers, or Habitat for Humanity or work with a anti-war group or any of the other groups that are working to make the world a better place. You can also build character by caring for you family and friends and standing by your responsibilities.

As far as bringing out the truth of one's self-- it is impossible for anyone who doesn't know you intimately to answer this.

Are you a dancer? Than dance will bring out the truth of your self. Are you a Martial artist, than martial arts will bring out the true you.

Dance is definitely truer for the true ebrown (specifically Salsa dance). But that probably doesn't mean anything for you.