A character playing a character quote

I couldn't find an answer in the submission guide so I hope someone can help. Let me explain with this hypothetical:

John Smith is a character in a movie. In the scene I'm quoting John Smith is going by the identity "Tom Brown"  Its important to understand this in order for the quote to make sense to a the reader. How to i properly format that to submit the quote? Does that make sense? If not I can try to explain it better.

Thank you