Rose was used to the whole mistaken identify by now, after knowing a few different versions of Elena and even having the fun misfortune to meet Katherine, not to mention the people who knew them both. She'd been mistaken for one or the other a few times before.
"Not a doppleganger," she promised. "I'm not even from your world. I was stuck in a place called Breck for a couple of years before this and I knew a bunch of your friends there. Damon, Elena, Caroline. I even had the fun of meeting Katherine, but she didn't stay long, thank god."
She waved off Bonnie's apology. "Believe me," she assured the witch, "this isn't the first time I've been mistaken for her. I'm pretty much used to it. People confused us all the time in Breck, even though Damon could always tell us apart. It's easier when you get to know me and he was one of my best friends there." It still hurt that he didn't remember any of it. They'd apparently been friends in that Lawrence place, too, but it wasn't the same when he didn't remember everything they'd been through. "I never got the chance to meet you before," she added, "but Damon talked about you a lot. He really missed you."