Translation:When do you think that she will tell you about her difficulty?
Probably. It can also mean literally "difficulty, hardness (of something)", like: when do you thin she will tell you that X is difficult for her?
Couldn't this also mean 'its difficulty', meaning for example 'the difficulty of the exam'. Then the translation would be 'When do you think that she will tell you about its difficulty (the difficulty of the exam)?'