Set in the Equestria Girls Universe (hence Human tag)
Sunset Shimmer never expected anyone to forgive her. Princess Twilight Sparkle was the first. She never expected anyone else. Five girls, whose friendship she destroyed, followed. It took her defeating the Sirens to get the rest of the student body to talk to her.
As she strives to make amends for all that she had done, there is really only one person who she wants to apologize to above all others. While she has said that she was sorry a hundred times over, there is still one person she has never told.
One pony she feels needs to hear it.