If she did not know better, madame Marissa would have been involved in a lot of fights for no reason. This loser tried to incite her to get involved in some fights but she had the good sense to probe what he had told her and that is how she avoided a messy fight. And for doing that, he had to be punished. She chose to use faceslapping to brutally teach him a lesson. Besides slapping him, she ballbusted him as well.