What are some unselfish things that Tom has done to Becky that show his maturity?

Becky tears the teacher's book, and Tom takes the blame.

“Susan Harper, did you do this?”

Another negative. The next girl was Becky Thatcher. Tom was trembling from head to foot with excitement and a sense of the hopelessness of the situation.

“Rebecca Thatcher” [Tom glanced at her face—it was white with terror]—“did you tear—no, look me in the face” [her hands rose in appeal]—“did you tear this book?”

A thought shot like lightning through Tom’s brain. He sprang to his feet and shouted—“I done it!”

Tom worries about Becky's illness and hangs around her house to get word of how she is doing.

ONE of the reasons why Tom’s mind had drifted away from its secret troubles was, that it had found a new and weighty matter to interest itself about. Becky Thatcher had stopped coming to school. Tom had struggled with his pride a few days, and tried to “whistle her down the wind,” but failed. He began to find himself hanging around her father’s house, nights, and feeling very miserable. She was ill. What if she should die! There was distraction in the thought. He no longer took an interest in war, nor even in piracy. The charm of life was gone; there was nothing but dreariness left.

Tom allows Becky to rest while he searches for a way out of the cave. He does his best to keep her calm and unafraid. He also decides to keep the presence of Injun Joe a secret to keep her from being afraid.

Tom’s fright weakened every muscle in his body. He said to himself that if he had strength enough to get back to the spring he would stay there, and nothing should tempt him to run the risk of meeting Injun Joe again. He was careful to keep from Becky what it was he had seen. He told her he had only shouted “for luck.”