What is the ruling on money earned from trading in cosmetics for women, knowing that there are women who are immodestly dressed who use them, and religious women who use them for their husbands, and does this refer back to the intention of the merchant?

Trading in women's cosmetics is permissible, based on the generality of Allah's saying, "And Allah has permitted trade and forbidden interest." However, if the seller knows that the buyer will use them for ostentation to non-mahram men, then it is not permissible for him to sell to her, because by doing so, he would be assisting in sin. Other than that, the default ruling is permissibility, and there is no objection to a girl agreeing to marry a person who works in this trade, provided he is a man of religion and good character.