What is the theme

How can one know that the stories people tell are the whole truth and nothing but the truth? This is one of the questions that operates on every level of the narrative starting with the story Nick is telling the reader. When her story starts, she leads readers to believe that Corrine was her best friend and that she is upset that Annaleise is missing. She also leads readers to believe that she loves Everett as she has agreed to marry him. Yet, readers soon discover that she has also been sleeping with Tyler when she comes back to Cooley Ridge.