Instructions
Talk to the non-player character, Moony, in the town, Amoria. She will ask your male character to prove his love for his soon-to-be fiance. To prove your love, you must bring back four Proof of Love items.
Find Nana in Amoria and speak to her. Her placement in the town is random, so you may have to hunt her down when it is time for you to find her. She will give you a quest to complete in order to get a Proof of Love item. The quest she gives is randomly generated. Because you need four items, you will need to do four quests for Nana.
Return the Proof of Love items to Moony. She will let you choose between four rings: Moon Stone, Silver Swan, Star Gem and Golden Hearts. Once you have made you choice, she will make the ring for you out of the items that you gave her.