"Yes your butt looks fat in that. Hey, I’m just being honest."
In this quote, the first sentence may be honest, but the second seems not. We do not just randomly choose when to be "honest," and to call attention to this honesty. A quick survey of the practice of "radical honesty" suggests that we are more likely to be honest with criticism of others, and with praise of ourselves.
Yes, you may think you honestly believe what you say, and you may see you have resisted social pressures to not say it. But before you call yourself "honest", take a moment to ponder under what sorts of situations people tend to say what you said, and what that tendency says about their likely motives. Don’t call yourself "honest" until you can also acknowledge those motives.