So people do this to signal (both to their spouse and their friends) they are both financially capable and care enough about their spouse to burn a large amount of money on a pyre. It's also a very useful signal that you are serious about the commitment and unlikely to back off of the marriage. I would prefer to replace it with a certificate that proves you have spent X thousand dollars on said certificate from Moche Silnorin Inc. A less personally-beneficial alternative would be some sort of modern dowery, the recipient of which is Moche Silnorin Inc, who holds on to the money until the culmination of the marriage, after which the dowery is given to the wife and so reunited with its giver once they share finances. If the engagement gets broken off, Moche Silnorin Inc keeps the money. However, this raises the possibility of bondsmen. Which isn't a possibility with diamonds, with their awful resale value. So perhaps just a non-refundable expense in exchange for proof you've given X thousand dollars to Moche Silnorin Inc would be ideal.