Don't hinge your business success on getting an unlimited number of humans to agree with your AI on an unlimited number of facts.

The universe of facts is infinite.

The larger a user base, the fewer facts they'll collectively agree on.

If you take on a large user base and an infinite knowledge domain, you'll lose trust with users who disagree with your fact checking (rightly or wrongly.)

Instead, give yourself a smaller scope where you can actually win. Train your tool to be a world-class fact checker in a specific domain. Then market to a userbase who explicitly already agree on the facts you check against. This smaller scope sets you up for technical success and builds experience, revenue, and user trust, all of which you can leverage to iterate into another domain more quickly.