What might be the reason for Mayella's crying in the court in To Kill a Mockingbird?
Although Mayella is 19 years old, she has no friends, rarely if ever leaves the Ewell property, and she has the mental capacity of someone much younger. Mayella first "burst into tears"--not at the questioning of Atticus or Mr. Gilmer, but when Judge Taylor asked her to just tell the court what had happened between her and Tom. The judge quickly recognizes that Mayella is not used to being out in public or questioned by others, and he treats her accordingly.
"Now you're a big girl, so you just sit up straight and tell the--tell us what happened..."
Later, Judge Taylor asks,
"What's the matter with you?"
"Has she got good sense?"
Jem believes she has enough sense
"... to get the judge sorry for her, but she might just be--oh, I don't know."
Mayella is obviously scared, probably because she plans to tell lies about what happened on the day that Tom Robinson paid her a visit, and she realizes that her story may not fool everyone. She becomes even more fearful when Atticus begins his questioning, and Mayella quickly becomes confused. She is a poor, ignorant girl, incapable of dueling in a battle of wits with Atticus. In the end, and after many more tears, she refuses to answer any more questions, and Scout thinks that
... if she hadn't been so poor and ignorant, Judge Taylor would have put her under the jail for the contempt she showed everybody in the courtroom.