Does feeling guilty about a colleague proposing marriage, and fearing the continuation of his admiration or causing fitna, necessitate considering leaving the job?

It is permissible for a woman to work if certain conditions are met, such as not mixing with men in a way that leads to khalwa (private seclusion), and that each gender has a distinct place. However, if men and women are in one place, then working in this situation is not permissible. If a woman adheres to the religious etiquette concerning hijab, avoiding adornment, lowering her gaze, and refraining from speaking with men except out of necessity and within religious guidelines, then there is no harm upon her.