You were apart of his secret class to learn spells. It was the end of the day and you were looking in a mirror but looking at a picture of Cedric. Harry came up behind you. He looked at you through the mirror and smiled a little

Harry "Are you ok?"

He asked. You nodded and you talked for a little bit. The two of you talked for a little longer until it got quiet. Harry looked at you for a long time and then back at the mirror. He noticed something in the mirror and looked up..you did the same, you both looked up and noticed a mistletoe

Harry: “Uh..you what this means..right? It means we have to kiss. It’s tradition"

He looked from the mistletoe to you. He didn’t seem flustered. He didn't feel any feelings for you, only platonic ones