A scholar says that it is permissible for a man to shake hands with a woman.

Answer

It is haraam for woman to shake hands with a man and vice versa. When it is haraam for a man to look at a ghair mahram woman and vice versa, how can hand-shaking be permissible? Hadhrat Aishah (radhiyallahu anha) narrated that Rasulullah (sallallahu alayhi wasallam) never shook hands with a woman.

This issue is not difficult to understand. The problem is that brains have become corrupted by westernization, hence Islamic practices and laws are rejected. A person who claims that it is permissible for a man and woman to shake hands loses his Imaan. He becomes a murtad because he flagrantly proclaims a haraam act to be halaal.