Is it a sin for me to establish an online store that displays goods which might be used for women's adornment (tabarruj)?

Selling items that can be used for both permissible and forbidden purposes falls into three categories: It is not permissible to sell them if it is highly probable that the buyer will use them for forbidden purposes. There is no harm in selling them if it is highly probable that they will be used for permissible purposes. If neither of these is known, the default is permissibility, and there is no harm in opening an online store.