Korra and Asami wind up a couple, but there are plenty of moments before that climactic moment in the show's series finale that hinted at their relationship. Vote up the moments that best foreshadow their relationship!
During the three years when Korra is recovering from her fight with Zaheer, Asami is the only friend from Republic City that she writes to. As she explains in her letters, she doesn’t feel comfortable explaining her lingering trauma to Mako or Bolin. At this point, the two of them are still just friends, but Korra’s decision to single Asami out shows how deep the bond between them is becoming.
Before Asami and Korra agree to take a vacation to the Spirit World, they spend a quiet moment remembering Asami's father, Hiroshi. Hiroshi was a complicated figure in his daughter's life, but the two reconciled before his passing, and he managed to pass a hero. It was a loss that Asami clearly felt deeply, and it's telling that Korra was the person she looked to for comfort as she dealt with her grief.
After Korra returns to Republic City in Book 4, she sits down for lunch with Mako and Asami. Before they’re interrupted, Asami comments on how great Korra’s new, shorter hair looks, and the comment makes Korra blush. She replies that Asami is looking “snazzy,” but the blush suggests that she’s harboring some feelings she may not be ready to acknowledge yet.
All the way back in season 1, Asami takes Mako, Korra, and Bolin to her father’s racetrack. Korra, who’s initially resistant to the idea of liking Asami, realizes that Asami’s a lot tougher than she may seem. It’s the first hint of a bond between Asami and Korra that has nothing to do with the men around them
After Korra's deeply traumatizing fight with Zaheer, she's temporarily confined to a wheelchair. Several weeks after the fighting, Jinora is named an airbending master, and it's Asami who spends the time before her ceremony getting Korra ready. She helps her get dressed, pushes her wheelchair, and assures Korra that if she ever needs anyone to talk to, she'll be there. It's a moment of deep connection between the two of them.
This is a small moment, but it speaks to the way that Asami thinks of Korra. In an episode devoted almost entirely to old clips, Korra and Asami have a conversation about how much things have changed since the two of them met. Asami brings Korra tea at the start of that conversation, and then serves as a buoy for Korra, reminding her of how much she's accomplished since she took on the role of Avatar.