A teenager named Roger is the protagonist of "Thank You, M'am" by Langston Hughes, and when we meet him for the first time, it is eleven o'clock at night and he is trying to steal an older lady's purse. Our first impression of him is the same one the woman, Mrs. Luella Bates Washington Jones, has at first: he must be a ruffian and hooligan.
Once the woman looks at the boy a little more closely, however, she discovers that he is rather dirty and unkempt in a way that makes her ask him who is taking care of him. Roger tells her no one is taking care of him, so she takes (okay, she pretty much drags) him home with her.
Mrs. Luella Bates Washington Jones makes another assumption about Roger: that he tried to steal the money because he is hungry and needed the money for food. Instead she learns that he wants a pair of blue suede shoes; that is why he tried to steal her purse. While it might seem rather silly to us, this is a serious matter for the woman. After a few moments of reflection, she says that she understands what it is like to want things and, in fact, has done some things she would never even tell God except that He already knows them.
After this revelation, the woman does something rather unexpected. She gives Roger an opportunity to either prove himself trustworthy or prove himself to be a scoundrel.
In another corner of the room behind a screen was a gas plate and an icebox. Mrs. Jones got up and went behind the screen. The woman did not watch the boy to see if he was going to run now, nor did she watch her purse which she left behind her on the day-bed. But the boy took care to sit on the far side of the room where he thought she could easily see him out of the corner of her eye, if she wanted to. He did not trust the woman not to trust him. And he did not want to be mistrusted now.
Roger is worried that she will think the worst of him, so he takes great care to make sure she knows he can be trusted. It is a grand moment for both of them, as she demonstrates her trust in the boy and he proves himself to be trustworthy.
Of course he does not expect to be rewarded for his decision, but he is. Mrs. Luella Bates Washington Jones gives him ten dollars for the shoes he wants, but when Roger does not have adequate words with which to thank her, we know that she gave him much more than that.
Roger was worried because he expected some kind of punishment from Mrs Jones or she would take him to the police.