The Lannisters are treating me very well and providing me with every comfort. I beg you: come to King's Landing, swear fealty to King Joffrey and prevent any strife between the great houses of Lannister and Stark.
Out of context, it looked bad.
Gilly was about to run into the end zone untouched and Sam pushed her out of bounds at the 1 and then punted on 1st and goal. Remember that Arya isn't aware Sansa wrote the letter under duress, so as far as she knows, it's legit evidence that her sister betrayed their family. That love turned out to be more creepy than endearing, though, like when he told the story of their ill-fated romance while asking two prostitutes to finger each other in his brothel, or when he brought it up again while pushing Catelyn's sister Lysa out the Moon Door.
There's nearly no downside for Littlefinger to the letter being uncovered which is exactly why he wanted Arya to find it.
Both were able to keep up the pretence of being their ideal when faced with adversity: Arya became Arry, Sansa became the lie of a dutiful wife to Joffrey (albeit temporarily). Sansa Stark was on the wrong side of all those moments, which cause the gears to start turning in the head of Arya.
The theory of Littlefinger waiting the battles out before using Sansa also suggests that the idea of him seeing her romantically is false. Then in Sunday's episode there were more examples of Arya doubting her sister and her sister's leadership.More news: Malala gets admission in Oxford University
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"She hasn't dealt with Littlefinger for a while, so she gets roped into spying on somebody who's actually leading her by the nose to something that he wants her to have", said Weiss. It's opportunistic... He has played his part in the rise of the Starks, showing up last season with the Knights of the Vale, but he will also undermine it and exploit it.
The second possibility though is far more enticing. Bran is already on to him, which is probably why he gave the dagger he received to Arya Stark (Maisie Williams), who he knows is a master assassin. Odds are she's a true-born Targaryen like everyone else around here-but for God's sake, don't ask her about it while she's finishing a drink. Why wouldn't she think that Sansa is still that feckless and disloyal, a girl who could once think of nothing but boys and dresses and being pretty?
So he's trying to turn her against her family to win her affections. "And he's good at it, you know?" When Arya sneaks into Littlefinger's room, she finds the note-exactly like he wanted her to. You could immediately see it on her face. Cersei has the captured women retrace her steps from the walk of shame and kills them with brutal creativity, something only Cersei could come up with and execute.
Littlefinger's latest plan is as good as any he has ever devised, but unfortunately for him it won't work on someone trained to identify liars. Ned once explained to Arya why Sansa acted like she did and Arya said, "I don't hate her, not really".
She's just a means to an end. After watching this week's episode of HBO's "Game of Thrones", titled "Eastwatch", she would likely agree with Samwell Tarly's decision to leave the Citadel midway through his training, even though it might mean abandoning his dream of becoming a maester, or doctor-scholar.