So that leaves me with a few questions...
When you use "la/le" for the article, before the verb, it's almost always because the object has been previously discussed in context, correct?
I'm native a native American English speaker, and adding the "it" to the phrase seems a little bit odd. I'd say he/she "wants (or does not want) to quit...." would be more commonly said, unless you add the "it" to clarify any confusion, because the previous context might not be perfectly clear.
Quitter can be translated as "to leave", so you I translated it as "she no longer wants to leave her" and it was accepted with "she no longer want to leave it" provided as an alternative answer.
My point being, since some words may sound better and still convey the same meaning of the sentence given, using a synonym may work if you find the first word that comes to mind sounds odd unless you omit some important parts of the given sentence.