From the University Writing Center (here in PCL!):
A thesis statement is the "point the paper argues or proves" and it should be contestable and focused. See the handout below from the Writing Center for more guidance.
But what does that have to do with research?
You craft your thesis statement AFTER you do your research. You have observed what has been argued about your topic and based upon what you have read, you are arguing, demonstrating or proving something.
I read that some critics/scholars think Rosemary is mentally unstable.
I also read that some critics/scholars think Rosemary is being tricked by her husband and neighbors.
I wonder if neither depiction tells the full story, and that the film is a metaphor for a woman's lack of control over her body and free will.
Thesis: In the film, Rosemary's Baby, the protagonist is portrayed as delusional, or perhaps gaslighted by her husband and friends, a state brought upon by her loss of personal autonomy.