There is a Golden Ring that is the reward item for a Quest from an NPC. I've seen it being used as an engagement ring and as a Wedding Ring. At the moment this item is unavailable, because the manner in which we interact with NPCs is currently being changed and there are issues with the process. These are being resolved. Getting Quests from NPCs will be restored. Have faith!
Longer term, there is provision in the Job Skills for Jewellry Making - a future crafting path perhaps, although my take on this is that will be less one to produce pretty trinkets but more to craft enhanced weapons - an Opale-encrusted Dagger comes to mind.
Have faith? Well, there is an NPC Merchant out there who has: He's waiting to buy Jewellry already!
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