My sister recently accepted a high-paying job offer as office administrator in a local firm in our hometown in India, run by a divorced middle aged financial consultant. She is due to join next week but has now been informed by very reliable parties with direct experience that this person, her future boss, is a habitual womanizer who makes subtle advances upon female employees to start an 'office romance' (euphemism for an illicit affair.)
My sister doesn't need the money but says that any future boss could be a womanizer we don't know of, and does not want to give up the job just for that reason. However she feels that if the boss makes an improper advance and she rejects it (even gently yet firmly) it could poison the atmosphere at the workplace. Although the person might possibly tolerate her firm but gentle rejection of his proposition, she would surely lose the job as a result, or else feel obliged to resign.
Goal: She is determined not to accept any proposition from him for an illicit liaison even if she loses the job as a result. How can she convey her unwillingness even before he thinks of making the typical 'romantic' overture? Actually talking about it with the boss is culturally impossible and would be considered a great insult here in the entire South Asian region, so her goal is to proactively prevent any such proposal by making it clear by her body language and general behavior that she is not 'available' even though she is an unmarried young person.
Is this even possible to convey through body language and general behavior and if so, how can she achieve this aim?
Note: these advances by the boss may very possibly be construed as sexual harassment at the workplace but she has no direct experience or evidence of it at this point and filing a complaint after rejecting an improper proposition is not my sister's goal here. She is not going to be a member of Stack Exchange at present but she will read the answers posted. I am familiar enough with the details to make any necessary clarifications. The interpersonal talent of our members is urgently needed here!