No one knew. She was different. I was different. It's all an untold story that's lost forever because the only person that would tell her secret is gone.
You have no idea who Klaus Mikaelson is to you. You have no idea who any of the Mikaelsons are to you, for that matter. Thing is, they seem to know you. If what they're saying is true, how are you going to get your apparently missing memories back?