What is the ruling regarding my fiancée, who wears the niqab, working as a seller of modest clothing in a store, knowing that I object to women working, but her family circumstances necessitate her going out to work?

It is permissible for a woman to work if the work involves lawful matters and does not include anything that violates Islamic law or exposes her to temptation. It may even be recommended if there is a need for it. So, if a woman's work does not expose her to private seclusion with men or suspicious mixing, then it is permissible. The suitor has no authority over his fiancée, and she is not obligated to obey him before marriage. However, after marriage, a woman is not permitted to go out to work except with her husband's permission, unless there is a necessity.