In the trial scene in To Kill a Mockingbird, when Mayella is testifying, what is Atticus afraid that the jury will assume?

Atticus could be afraid that the jury will believe that
her lies are true just because she is white. It is obvious to the reader that she is
lying but the narrator has to use language like her performance or recital to let us
know that she has practiced what she has to say. If you are telling the truth, you don't
have to practice it, you just have to remember it. The jury doesn't have either the
benefit of living 80 years after the incident like we do, nor do they have the benefit
of having the narration of Harper Lee. All they have are Atticus' leading questions and
Mayella's white testimony. Atticus fears the jury assuming lies to be
truth.