Why do you need an email? You can use a trusted person in the forum, everyone sends gold to him and after he is sure of the quailty of gold he tells you to send the money to the second party.
Selling gold requires trust and you will only get it through people who know the forum and work for a long time.
Have you confirmed the legal status as buying and selling of gold involves some legal waste?
you don't buy sell gold ... to buy / sell gold you have to give fiat ... crypto has legal status as commodity in most countries ... so crypto4gold is "bartering"
The only thing you buy is crypto so you can trade it for gold/silver