where u get the ring from is not important, no one can see the brand when it is on her finger. half of the price is paying for the brand itself. 2 main reasons why it needs to be certified, 1st, to make sure the authenticity. so that the jeweler cnnot con u. 2nd, if later in future u wanted to sell the ring, only certified diamond can be re sell (to jeweler, pawn shop etc), it means no cert=tak laku or one one would buy it. there's a few certs, common one is gia, ags, egl etc. well 6k can get u a descent one, prob, 0.4-0.5 carats. safer choice is always go for branded jeweler, but price are crazy, look for sales, nowadays habib wah chan etc got like 50% off sometimes, can get good deal. read ads in newspaper, usually always got one. if u have bigger budget, always go fot the big shiny ones cause thats how a man make a statement on his wife's finger