She just has her things that she cares about and I try to respect that when I'm getting stuff for her, especially something that will be this meaningful to her. If I bought her a used ring she'd just spend her time wondering about who's nasty finger it was on first.
I highly recommend Van Adams in Snellville. I bought my wife's diamond there 15 years ago and everywhere she goes the women are awed by it. He is Vietnamese and travels to the Orient to buy his diamonds and then sets them in his custom designs.
His prices are very competitive and he stands behind his work.
Take her there. You won't regret it.
Pm me and I'll let him know you are coming.
My wife's ring is currently appraised and insured for over two times what I paid for it.