This is an interesting question. It seems to me like they were trying to play the two of these as good friends before the attacks and Sharon's reveal as a cylon, but it never really worked for me. I never felt the bond that the dialogue seemed to imply. It seems much stronger between Helo and Kara or even Kara and Crashdown (during cardgames). Maybe it's because they didn't have that much interaction. Maybe because Sharon's reveal was so close to the beginning of the show? Not sure. Even the scene later when Kara visits her in the brig, I know they were referencing some past connection, but I don't even remember Kara reacting to Sharon as a cylon in any reflective way. Yeah, she gave Helo a lot of shit about it, but no reflection of Kara's own personal feelings of betrayal. It is possible that I am forgetting some scene completely...