This is a giant enormous issue to tackle. I would recommend you approach this manually similar to how twitter deals with it.
You can set custom titles on users. So once you confirmed a user really is who they say they are you can add a “Verified” title to the user. You have plenty of ways of confirming:
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If you have Twitter auth enabled you can look at the Twitter account they have associated and see if they are “verified”
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If you know the email… well that is easy you can just flag it as verified
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You can start a conversation with users and even call them in rare cases.