Maria Shriver -- Second Thoughts About Divorcing Arnold Schwarzenegger

Maria Shriver is telling friends she's now unsure if she wants to divorce Arnold Schwarzenegger ... TMZ has learned.

We're told Maria is torn, partly because of her strong religious beliefs that do not include divorce.

Making matters even more complicated -- we're told Arnold still desperately wants Maria back, and has been "extremely sweet" to her and has made numerous gestures -- which include presents -- to win Maria back.

Maria filed for divorce on July 1, though she moved out months earlier. She's already bought a mansion in Brentwood, CA, which she's in the process of renovating.