In the US, a person who is clearly mentally ill and commits a crime is prosecuted for that crime as if s/he were well. The "not guilty by reason of insanity" verdict applies *only* if the person's illness prevents him or her from assisting in their own defense. (TV and movies get this wrong sometimes.) However, in many cases the prosecutor is not a monster who wants to lock away someone who's mentally ill.
Often there is a plea deal reached for such people in which their sentence is commuted to a long stay in a state mental health facility, or a secure private facility if they can pay for it. If a mentally ill person is convicted and sent to prison, they're in with the general population, where there are quite a few others. Faking mental illness is quite difficult, and in the US, pretty much pointless, since the odds are good that you're going to prison unless it's clear to all that you've been mentally ill for years and years, in a way that negatively impacts every aspect of your life.
A sudden slip into mental illness shortly before you commit some felony is entirely too convenient and prosecutors are going to challenge that.
Usually, she would probably be sent to a mental facility, to be assessed. If the dr finds her 'normal', she would be sent back to be judged. If not, she's be kept there until she is treated (if she can be) then sent back to be judged.
You aren't supposed to keep mentally ill patients in a normal jail. But, it depends. Lots of countries don't follow this protocol.
Since this is a story, she can be unfairly sent to jail/ not get her sentence reduced/ govt doesn't have the facilities, so she gets sent anyways, etc.. Edit: as for faking it...well either the doctors have to be terrible at their job/ have ulterior motives to not catch someone faking it. Usually more than one dr makes the diagnosis.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.