You know the answer to that is zero. There is no viable system a company, let alone a small unfunded startup, could use to verify the identity of the reporters let alone guarantee the trustworthiness of the account.

Those ten reports could be made by one person. That one person might not even know the person they're accusing. That one person might be a man. That one person might be a bot.

You'd have to ignore the last three decades of online identity, trolling and social media pitfalls to not recognize that.

And please don't compare reviewing a can opener on Amazon to accusing someone anonymously of a heinous crime on an app built by one person.

But I'm not sure I'm going to convince you with words so I'll suggest this:

Go and build this app.

Build it, see what happens. Nobody else has been able to crack this but maybe you can.