People can change. At the beginning of the story Jimmy's passion was to rob banks. Now that he's fallen in love his passion is to help the people he loves. He gave up what he wanted to do for someone he cared for more.
One mood that is set towards the end of the story is suspense. Ralph's soon to be wife's sister brings her kids to the bank to see the new safe. The combination had not been set and one sister locked the other in. This is suspenseful because we don't know what's going to happen.
One example of foreshadowing in this story happens with Ben Price. On the day Jimmy has his tools in town and Agatha ends up getting stuck in the safe Ben Price happens to be in town. Ben sees "Ralph" in his shoe shop and he starts to get suspicious.
One character trait shown by Jimmy is how sly he is. He was able to get his prison sentence shortened from four years to ten months. Then he was able to get away with robbing many more banks before settling in Elmore.