How do we know that Tom is maturing.

Over the course of the novel, we see distinct changes in Tom, as he matures and learns to see beyond himself, to consider others.... In the beginning, Tom is a master manipulator, he knows exactly what he wants, and he does whatever is necessary to get it..... regardless of how it affects others. As time goes on, Tom actually begins to see the repurcussions of his own behavior, he learns to empathize, he acquires a conscience, he comes to understand the value of forgiveness.

One example of this can be found in Tom's reaction to Aunt Polly's tears, her grief at his supposed death.

" 'I wish now I'd thought,' said Tom, with a repentant tone; 'but I dreamt about you, anyway. That's something, ain't it?' "