What should the questioner do after he refused his fiancée's job as a receptionist at a language center, and then was surprised to find that she had accepted the job?

Your fiancée is not permitted to work in the center if her work entails an impermissible religious act such as khalwa (private seclusion of a man and a woman who are not close relatives) or ikhtilat (unrestricted mixing of genders). You should advise her to avoid forbidden acts without being in khalwa with her. If she does not comply, you have the right to prevent her after marriage. You are not permitted to agree to her condition of continuing this work if it leads to corrupting influences. We advise you to leave her and seek a righteous woman.