In the first few minutes of Frozen (2013), Elsa (Idina Menzel) accidentally hits Anna (Kristen Bell) with her ice magic. Their parents take Anna to see a group of trolls they know have the ability to heal the wound. Kristoff (Jonathan Groff), a human boy who lives with the trolls, witnesses the event from the sidelines.
Years later, Elsa accidentally freezes Anna’s heart when she’s in the company of Kristoff. He suggests they go see the trolls because they can help her. When Anna inquires, Kristoff responds “I’ve seen them do it before.” He clearly remembers witnessing the trolls heal Anna as a child - but does he realize it was her? Or does he simply remember seeing it happen to someone?
Personally, I’m going to vote no, he didn’t remember who it was happening to. He just knew it was something he witnessed and that the trolls could help. Generally people don’t remember things from their childhood with a lot of vividness. Large overall events, yes, but details like faces and streaks of white in the hair, I doubt it.
It’s a speculative question, but one online theory offers an answer more confident in Kristoff’s memory than my own:
“Kristoff may not have initially known that he had seen the royal family as a boy. But because he grew up with the trolls, he would have asked about what he saw and learned the truth. In that case, Kristoff had learned that Elsa had ice powers and Anna was healed by Pabbie before. In Anna’s case, Kristoff may have been told that she had a white streak in her hair from being struck by Elsa. Now it’s not made clear if he notices it before Elsa strikes her again, but it is made perfectly clear when he sees the streak grow bigger and turn more of her hair white.
When she asks if it looks bad, he only hesitates because he is thinking about the last time he saw a girl with a white streak in her hair. He scrunches his eyes, trying to remember, then his eyes widen because he not only realizes that Anna was the same girl he saw, but because he knows what her fate will be if she does not get help. And he realizes that there may be one hope for her survival: the trolls."
Wide eyes in Frozen seem commonplace to me, but you be the judge.