First, model it. Second, when you spot it, affirm it—especially when honesty costs something, as in confession. When a child confesses something—perhaps he broke something—the first thing to do, before correcting the mischief, is to commend the honesty. Make a big deal out of the trustworthiness of honest people, how confidence in them grows as they make a pattern of telling the truth and how much courage it takes to tell the truth when there are consequences.
