What is the ruling on dealing in items used by women for adornment and selling them to women whom the vendor knows will wear them in order to flaunt themselves before non-mahram men in the streets, as he can see from the way she looks in front of him, and as is unfortunately widespread in some places?
Praise be to Allaah.
It is not permissible to sell them if the businessman knows that the person who buys them is going to use them for things that Allaah has forbidden, because this means that he is cooperating in sin and transgression. But if he knows that the purchaser is only going to wear them for her husband or he does not know anything, then it is permissible for him to sell them.
From Fataawaa al-Lajnah al-Daa’imah, 13/67