Besides Jon, who do you see as a candidate with a good chance of being a romantic interest for Sansa? I don't know if George Martin will even include that in an endgame but considering Sansa does want someone to love her for who she is, I'd hope he'd at least allow her some happiness in that regard.
I am actually pretty optimistic about Sansa getting a happy ending; primarily because “no one will ever marry me for love” and “life is not a song,” and “there are no heroes, in life the monsters win” are so incredibly prevalent in her arc. Sansa’s character arc is basically a “Captive Princess in the Tower”— but deconstructed, and then reconstructed, and then ~kind of~ deconstructed again and also ~kind of~ flipped on it’s head. But regardless, a fairy tale is still a fairy tale. Honestly the entire ASoIaF series is one ridiculously long, intricately detailed fairy tale. Which leads me to believe that, for the most part, all the protagonists will get their happy (or at least bittersweet) endings.
Above everything else, Sansa wants to be loved; and through out the series she has become more and more convinced that she never will be, that she is unlovable. Aside from retuning home to Winterfell, its still her heart’s dearest desire. She does still want a loving, happy marriage, she just doesn’t think it’s possible anymore:
But then she remembered what Dontos had told her in the godswood. Tyrell or Lannister, it makes no matter, it’s not me they want, only my claim. —Sansa, ASoS
It is not me she wants her son to marry, it is my claim. No one will ever marry me for love. But lying came easy to her now. “I … can scarcely wait to meet him, my lady. But he is still a child, is he not?” —Sansa, ASoS
It’s not that Sansa has given up on love, its that she thinks love has given up on her. It’s not necessarily that she’s rejecting the idea of falling in love and being happily married, she just doesn’t see it happening for her. Which breaks my gd heart oml.
Now moving on to your actual question (I know, I ramble. It’s so terrible!)…