What is explained?

Chapter 28

This quotation explains a great deal about Huck's increasing maturity and understanding of morality, as well as his keen observations. What is explained?

"I see I had spoke too sudden and said too much, and was in a close place. I asked her to let me think a minute; ans she set there, very impatient and excited and handsome, but looking kind of happy and eased-up, like a person that's has a tooth pulled out. So I went to studying it out. I says to myself, I reckon a body that ups and tells the truth when he is in a tight place is taking considerable resks, though I ain't had no experience, and can't say for certain; but it looks so to me, anyway; and yet here's a case where I'm blest if it don't look to me like the truth is better, and actually safer than a lie. I must lay it by in my mind, and think it over some time or other, it's so kind of strange and unregular. I never see nothing like it. Well, I says to myself at last, I'm agoing to chance it; I'll up and tell the truth this time, though it does seem most like setting down on a kag of powder and touching it off just to see where you'll go to."