In the novel To Kill A Mockingbird, what does Tom Robinson say during his testimony that contributes to a guilty verdict?

In Chapter 19, Tom Robinson takes the witness stand and describes his background and interactions with Mayella Ewell. Atticus begins by questioning Tom as to why he was convicted of disorderly conduct. Tom explains that he got into a fight with a man and went to jail because he couldn't pay the fine. Then, Atticus asks Tom if he's ever spoken to Mayella before, and Tom admits that he has. He explains that Mayella asked him to help her with many chores and that he frequently offered his assistance when she asked. Tom tells Atticus that he was never paid for his services and refused to take a nickel from her. Later on, Mr. Gilmer cross-examines Tom and asks him why he went out of his way to help Mayella without excepting any type of payment. Tom says, "I felt right sorry for her, she seemed to try more'n the rest of 'em---" (Lee 264) Scout mentions that "the damage was done" and that nobody liked Tom's answer. In 1930s Alabama, a black man feeling sorry for a white person was unthinkable. Tom's answer was taboo, and the jury viewed him with contempt because of it. By telling the prosecutor he felt bad for Mayella, Tom hurt his chances of being acquitted and was eventually found guilty.