How can the seller or employee know if the clothes being sold will be used for what God has forbidden?

The women's clothing sold by merchants in their shops falls into one of three categories: 1. If the seller knows or strongly believes that the clothing will be used in a permissible way, then the sale is lawful. 2. If the seller knows or strongly believes that the clothing will be used in a forbidden way (such as wearing it in front of non-mahram men), then the sale is unlawful, based on the Almighty's saying: (And do not cooperate in sin and aggression). 3. If the seller is unsure how it will be used, and the garment is suitable for both uses without any preponderant indications, then the sale is lawful, based on the Almighty's saying: (And Allah has permitted trade).

Anything that is used in a forbidden manner, or is strongly believed to be so used, is forbidden to manufacture, import, sell, and promote.