A wide gap usually traces to one of a few causes: one agent used stronger, more recent comparables while the other reached for weaker or older ones; one accounted for a permitted improvement the other missed entirely; or one number is priced to win your listing rather than to reflect what buyers will actually pay.
The higher number deserves the most scrutiny, since an agent motivated to win a listing has an incentive to price optimistically and then negotiate you down once the house sits unsold. Ask directly whether the price reflects what has actually sold recently or what the agent hopes a buyer will pay.
A hand-reviewed valuation that documents the comparables, the adjustments and any improvements made without a permit gives you a third, independent reference point to judge both opinions against. Get your hand-reviewed valuation from Joel Dyck.