Fred/Helena and whoever else is good people!
Helena could tell that look, she knew it well enough. He was disappointed. She was ruining his fun night because she hadn't wanted to come out and now it was showing in the way she was acting. She was such a horrible friend.
With a more genuine smile, she shook her head. "No, no. Lets stay. You did say you wanted to introduce me to your roommates after all." She already knew Harry and she had vaguely met Sirius just last week at his own party. She was sure she could stomach that for now.