Her face is close enough, if you've only seen a photo or a holo. Right height, right weight. Her voice is close enough, too. Accent, vocabulary, everything suggests this is Tahaki Karin.
She isn't, of course, but you've been forewarned. Anyone who knew the original would find themselves hard-put to detect the mimic. There are little things, though. The scar on her neck is newer. Her nails are filed smooth rather than roughly clipped. And she listens. To everything. She doesn't make a point of it, of course. But she's taking in everything. The whine of the electrical system, the buzz coming off the gravity plating.
Who is she, really? You don't know. But she's closer to being Karin than she is anyone else. Close enough.