How does huck learn to be honest?

I think Huck always was honest when it came to the larger scope of life. Like Tom, Huck always had an internal moral code; he just needed the life experience to develop it. Money never really means much to Huck. Indeed Huck discovers that money forces him to be tame. Huck craves adventure; he seeks to live in the moment amidst the splendour of nature. To Huck, the concept of money is "bye and bye". During his adventures he sees what money makes men into (the Duke and King) and he sees the victims that greed leaves behind. This just confirms Huck's value system. Huck concerns himself with setting things right (like with the fatherless sisters in the village). Honesty also means being loyal to his friend Jim and risking his life to do the right thing.