Ron Weasley.

Ron wandered through the train corridors with a look of worry, unease, and doubt. He frantically searched the carriages for his friends, Harry and Hermione, but so far he hadn't found them. They always shared a carriage, but this time, they weren't on the train for that. They must have been late.
In any case, Weasley continued to briskly walk through the vast corridors, peering through the glass doors of each carriage. During one of these moments of observation, he spotted a girl, a beautiful girl. She was sitting alone in a closed carriage, watching the scenery rush by with the movement of the train. Ron, inexplicably drawn to the girl who seemed to be his age, entered the carriage, closing the door behind him. "Good morning, miss. Or is it already afternoon..." he said, in his usual awkward and shy manner.