Which guarantor to choose?

Question

User interface

Tell me urgently I need a site-guarantor of transactions. I take on a large site and the customer is worried about who uses what? What and how best to do? The client is remote.

Answer 1

https://www.fl.ru/promo/bezopasnaya-sdelka/
https://freelancehunt.com/service/safe
https://freelance.boutique/fairplay.html

Answer 2

Freelance exchange.

Answer 3

Divide work (and pay, of course, too) into small, but logically completed parts.