You may post here instead:
https://forum.lowyat.net/topic/3224055

Wedding bands are used during vow exchanges.

For proposal, use engagement ring instead. The one that usually comes with diamond.

And yes, diamond do not have any value after purchase. Unless you plan to upgrade it gradually, you can still retain almost 100% of the value and top up the difference. But only limited vendors offer this.

Tiffany and Co? Overpriced. If you like the brand and can afford, no need to give a damn lol.

Nowadays don't necessary need a diamond, can use other precious gemstones as well, such as Ruby or Sapphire. You can look for La Fiancee or The Gem Tribe for options.

If you or your friend insist on diamond, you have much more options than you can think of. In Malaysia, you already have jewellers that are not running chained brick-and-mortar stores such as Memory Jewellery, iDo Jewellery, ZCOVA, Tailored Jewel, Eumayco, La Fiancee, The Gem Tribe, etc.

If you are interested to buy from the states, you have Whiteflash, Brian Gavin Diamonds, High Performance Diamonds, etc. They all ship to Malaysia and provide you with some of the best cut.

Nearer to home, we have Jann Paul in Singapore that provides top-notch diamonds as well.

Surely, they are all cheaper than Tiffany & Co.