Juliette finds out that Warner has kept her private notebook.
Do you know how many times I've read this?
Warner begins to read Juliette's notebook to her.
I sit here every day...
Warner embarrasses Juliette by reciting it from memory.
He's reciting it from memory.
...So I sit here. I sit here every single day.
Please. Please stop.
When Juliette was stuck in the asylum, she kept a notebook with her thoughts in it. Now her enemy and would be killer Warner has it in his hands. Juliette does not know what to think of it.
Either to get under her skin or another unknown reason, Warner begins to read from Juliette's notebook. This causes her to feel embarrassed and petrified because he won't stop reading.
This scene is important because it tilts Juliette's world. No one ever read her thoughts. Even her boyfriend Adam never laid eyes on him. Then this boy who tried to kill her, Adam, and the people she loved knew her darkest secrets. He knew her thoughts by heart and that to her is terrifying.