Signs of fraud: wire transfer, money orders, cashier checks, payment via gift cards, shipping, escrow, "transaction protection", "guarantee". Be safe by dealing locally.
With that being said, make sure that you find a good store that offers you the facilities any modern jewelry store would. Be it luxury watch store Miami or diamonds or perhaps a custom ring service, Buchwald offers you everything under one roof! https://www.buchwaldjewelers.com/watches.html