Brianna was aware that Quentin's words make sense. After all, Kendra was in Quentin's life much longer than Brianna is, and it is normal that he is curious if he suspects that Kendra is doing something behind his back. If the roles are reversed, Brianna would have similar questions as well.
However, many years of being together, also mean that they formed some connection. Trust probably. If Brianna says anything damaging to Kendra, will Quentin think of Brianna as a bad person? She is not sure.
