I thought of this as a song to someone she wants to be with, but can't because he only sees her as a friend. And he doesn't understand that's how she feels about him so he says things that people say to their friends (in this case maybe really close friends?) like "oh, I love you" "I'm glad you're my friend" all those kinds of things, and they hurt her because she wants them to be true, but knows they aren't.
I thought of this as a song to someone she wants to be with, but can't because he only sees her as a friend. And he doesn't understand that's how she feels about him so he says things that people say to their friends (in this case maybe really close friends?) like "oh, I love you" "I'm glad you're my friend" all those kinds of things, and they hurt her because she wants them to be true, but knows they aren't.