Hard to tell... the listing doesn't indicate which lab certified the diamond. Assuming it's a GIA or AGS-certified stone, then the ring is indeed selling for a bit of a discount, when compared to the diamonds that show up in the diamond search. Maybe the seller would rather have $96,000 in hand than an arguably more valuable ring in stock?
Diamond are similar to gold with the market being very price competitive, the same as gold. If it's too good to be true, then it's probably too good to be true.