Yeah, Sansa's really changed a lot now and I agree that it has a lot to do with a different upbringing for her because she's expected to be a Lady.
That's why I hope what she says is true that no fool should trust LF. She's a lot smarter now to even believe anything he says especially if he tries to start a rift between her & Jon. I'd like to think that she'll be there for Jon and eventually I hope they banish LF to the South.
But of course I'd want LF & Varys to meet again before LF is killed off on the show.