[Boaz]

If Sansa remembers her roots, she'll forget how to play the game... ie. she'll lose badly like her whole family did.

I think that Baelish knows that he is the master player and he'll think he can anticipate all of Sansa's moves regarding him. Sansa will have to become the Columbo of players to throw Baelish off the scent. If she can get him to completely underestimate her, then she might stand a chance, if not... he'll see her coming a mile away.