Rob - Sonny Corleone never said the Friendship line. It was an excahnge between Tom Hagen and Senator Geary at the Whorehouse run by Fredo in GF2.
GEARY
I passed out.
[He stands up and moves over the bed where we see a bloody dead girl.]
I -- I'll fix it.
[He unties the girl's hand from the bed post.]
Just a game.
[He takes a towel and begins to wipe up the blood that is all over her. He looks at the towel and wipes off his hands.]
Jesus, Jesus.
[He begins to cry. As he does, TOM looks over at NERI who is wiping his hands in the bathroom.]
Jesus, God -- Oh, God. I don't know -- and I can't understand -- why I can't remember.
TOM
You don't have to remember -- just do as I say. We're putting a call into your office -- explain that you'll be there tomorrow afternoon -- you decided to spend the night at Michael Corleone's house in Tahoe -- as his guest.
GEARY
I do remember that she was laughing...we'd done it before -- and I know that I couldn't've hurt -- that girl
TOM
This girl has no family -- nobody knows that she worked here. It'll be as if she never existed. All that we have left is our friendship.
wil.