I am trying to figure out how to get the engagement ring from Archibald and give it back to the woman in Dernhom, but he refuses to speak with me. I spoke to his son, so I know what is goin on. Help!
Actually, even one level of persuasion will do it. Just go away and adventure until you level, buy a point of persuasion and finish the quest.
There are other ways I never put much in persuasion (and I can see that I ought to) but you can either kill Archibald when he attacks you, or you can just beat him senseless and take the ring. Not as subtle as persuading him, but it still works. (To subdue him you need to get yourself down to bare fists and pound on him for a while. His fatigue will go down faster than his hitpoints.) Hmmm... Third time through I'll have to take some persuasion points.
You need persuasion in order to complete this quest PEACEFULLY. You will need to convince Archibad that the woman has taken a liking to him. He will ask you to send the ring back to the woman, along with his regards. You can also get 50 gold(?) from him by pestering him that you need some money to do the job. Talk to the woman and give her her ring and the quest is completed.