Authenticity can be verified by checking the logo on the clasp, the quality of the finishing, the engraved serial number, and the movement of the watch. For absolute certainty, take it to an authorized Hublot retailer.
Check for discrepancies in the logo, craftsmanship, serial number engraving, and the movement of the watch. Authentic Hublot watches showcase meticulous craftsmanship which is often lacking in fakes.