Drawing lines, why?

Ally: "Billy. You know what I said before about drawing lines?
I´ve thinking a lot about... We say we're friends like it's a consolation prize... the truth... for me... it's that our friendship is the greatest thing I got going. I cherish it. I don't to put honesty boundaries on it."
Billy: "Me neither.
So?"
Ally: "Free fall with the truth. Hope we both survive. Deal?"