"Thank you, M'am" is an incredible story by Langston Hughes exemplifying the Harlem Renaissance. If you need to take a look at only one set of character traits, you only have two to choose from: Mrs. Jones and Roger. These are the only two characters in the story. I consider Mrs. Jones to be the main character, so that is the character I will focus on in answer to your question.
Mrs. Jones full name is Mrs. Luella Bates Washington Jones. Her behaviors certainly show what kind of person she is: full of dignity and pride, always expecting the full potential out of other people she meets. Roger is one of those people from which she expects full potential. Ironically, Mrs. Jones meets Roger as he attempts to steal her purse. Always a non-judgmental person, Mrs. Jones adopts Roger as a kind of moral mentor, showing her compassion and kindness to others as a result. Mrs. Jones is a perfect candidate for compassion towards Roger. She has been through rough times when she "wanted things I could not get."
[I had]done things, too, which I would not tell you, son—neither tell God, if he didn’t already know.
Sharing a rough past is a perfect way for Mrs. Jones to connect to Roger. She shares both her humility and her morality and her faith with Roger. Through these things, she convinces Roger not to steal, especially for something as silly as shoes. Mrs. Jones not only gives Roger the money to buy the shoes, but also shares her meager food with him. A true role model, Mrs. Jones proves herself to be both honest and sincere.