Can I shake hands with the opposite sex?
Scholars differ Family & relations
Short answer
Scholars differ. The majority hold that a man and a woman who are not related as mahram should not shake hands. Some contemporary scholars allow it in necessity or when it is the custom and there is no desire. At the least, do not insult the other person; explain kindly that you do not shake hands, and put your hand on your chest as a greeting.
This is general information, not a fatwa. For your own situation, ask a qualified scholar.