At the start of both the book series drastically different in the books vs. the TV show.
Sansa's characterization and story understandably gets a lot more attention in the books, so there are certain facets of her character that only book fans know. But, what are those facets exactly?
She Had A Huge Crush On Waymar Royce
Although most Game of Thrones fans won't even know his name, Waymar Royce is one of the most memorable characters in the series simply because he's one of the first people who ever appears on screen.
Waymar Royce is the son of Yohn Royce, the man who becomes one of Sansa's closest advisers in the series, and Sansa falls head over heels in love with Waymar when she meets him at Winterfell, where he and his father stop on their way to the Wall.
She Nearly Married Loras' Brother, Not Loras
The Tyrell family is considerably larger in the books than it is in the series, and Margaery and Loras actually have two elder brothers, Willas who is the oldest and heir to Highgarden, and Garlan.
When the Tyrells attempt to plot to marry Sansa into their family, it is Willas that they intend to marry her to, not to Loras, but their plans are foiled by the Lannisters in the books as well.
She Thinks Of Lady Often
Lady's death in the second episode of the series is a heartbreaking and brutal introduction into the world of courtly life with the Lannisters for Sansa Stark. However, once Lady is dead, she's hardly mentioned again, and seems to be entirely forgotten by the second season.
In Sansa's point of view chapters, it's clear that she thinks of Lady often, as she likely had a warg bond with the wolf that was broken when Lady was killed.
Tyrion Actually Chose To Marry Her
The show presents the marriage between Tyrion and Sansa as an unwilling match on both ends, but in the books that isn't entirely true.
Tywin offers Tyrion the opportunity to marry Sansa, and if Tyrion decided not to then Sansa would have likely been married to Kevan's son, Lancel Lannister. Tyrion is initially reluctant, but considers the offer and decides to do it, in large part because marrying her would make him the Lord of Winterfell.
She Doesn't Have Much Of A Relationship With Shae
Within the TV adaptation, Shae is one of the only people who seems to genuinely care for Sansa as a person, and they develop a pretty close relationship when Shae acts as Sansa's handmaid.
In the books, Tyrion's whole plot to hide Shae in plain sight is pretty similar to how it plays out in the series, but Shae and Sansa don't actually develop a personal relationship.
She Never Married Ramsay
After Sansa is taken from King's Landing by Petyr Baelish, the storyline that she has in A Song of Ice And Fire is drastically altered for Game of Thrones.
The biggest deviation from her story is obviously her returning to Winterfell and being married off to Ramsay Bolton. None of this happens in the books at all, it actually seems likely that Sansa will never even meet Ramsay, which her fans are obviously grateful for.
But Her Best Friend Jeyne Did
Although Sansa has nothing to do with the storyline in Winterfell with Ramsay and Theon, that storyline itself didn't come from nowhere.
What actually happens in the books is that Sansa's best friend Jeyne Poole is married to Ramsay, but Ramsay is pretending that Jeyne is actually Arya Stark in order to give some veil of legitimacy to his claim over Winterfell. Unfortunately for Jeyne, Ramsay is as good a husband to her as he was to Sansa in the show.
She's Still In The Vale
Sansa ever marrying or even coming into with Ramsay Bolton seems so unlikely because, as of the end of the latest released book, Sansa is still in the Eyrie with Sweetrobin Arryn and Petyr Baelish.
She's still posing as Petyr's daughter Alayne, and as the Lady of the Eyrie is gone since Lysa's death, Sansa is essentially acting as the Lady of the Eyrie in her stead.
Robin Arryn Loves Her Very Much
Despite being cousins, the relationship between Robin Arryn and Sansa didn't get a whole lot of development in the show. They interacted a few times, and Robin was his typical bratty self with her.
But in the books, Sansa has taken on a significant caretaking role for him since his mother died, and it seems like Sansa (who he still knows as Alayne) is the only person around him that he actually loves or trusts.
She's Almost Engaged To Someone Else
Another element of Sansa's drastically different book storyline is that she's not only in the Vale, but Littlefinger is trying to arrange a marriage between her and a character named Harry Hardyng.
Similar to the TV show, Robin Arryn is a sickly little boy, and if he dies then it's Harry who will inherit the Eyrie. However, arranging the match is no easy task, as Harry is a highborn lord and he believes that Sansa is just the bastard Alayne Stone.