To ensure that you're purchasing an authentic bottle of ULTRAVIOLET, it's essential to buy from reputable retailers or the official Paco Rabanne website. Look for features such as proper packaging, a unique serial number, and a distinct fragrance profile that matches the brand's descriptions. Additionally, be wary of heavily discounted prices or suspiciously low-quality packaging, as these may indicate counterfeit products. By purchasing from trusted sources, you can enjoy the authentic quality and authenticity of ULTRAVIOLET.