The woman was telling the people about Peter being with Jesus. She probably did not know Peter's name.
## But Peter denied it ##
"But Peter said that it was not true"
## Woman, I do not know him ##
Peter did not know the woman's name. He was not insulting her by calling her "woman." If people would think he was insulting her, you could use a culturally acceptable way for a man to address a woman he does not know, or you could leave out the word.