Is it permissible to work as a cleaning lady for a few hours a month for Christians, knowing that it is not a necessity and she has no prior experience in cleaning, and is there humiliation in that?

The basic principle is that a woman should remain in her home and not go out unless there is a legitimate need. By doing so, she protects herself from temptation and its causes, especially in lands of disbelief where allurements are abundant. If you do not need to work, then stay in your home; that is better for you. As for the ruling on the

work mentioned, it is covered in Fatwa no. 144077.