It's tricky. 'Kept Woman' could be based on a real situation, but it might also be a completely fictional creation. Without more information, it's difficult to know for certain.
It's possible. Sometimes such stories come to light through personal accounts or investigative journalism. However, determining the authenticity can be challenging.
It depends. Sometimes stories are inspired by real events but have fictional elements added. So, it might have some basis in truth but not be completely true.
I'm not sure specifically which 'woman kept as breeding slave story' you are referring to. There could be many fictional or unfortunately real - world historical accounts that might fit this description. It could be about the inhumane treatment of a woman forced into a situation where she is made to bear children against her will, often in the context of slavery or extreme oppression.