My wife and I divorced. My wife faked marriage with an Australian woman and engaged in public relations. Can he vouch for me to go to Australia? Will there be a problem with my authentication?

Dangerous, because the visa officer will ask you about your relationship with the guarantor.

You divorce your lover; Your lover faked marriage with an Australian woman; Get a pr divorce, and then your lover remarries you, so you can go to Australia with your relatives. Many people in Britain do this, and it's nothing.