Okay, let's try something a little less known than last time (I just know I'm going to regret it though).
To take an item I cannot use, I must endure harm to "prove" that I am not harmed. If I was not harmed, I could use the item, but until I am the item will not exist.
What is the item, and what harms me?
This makes me think of several things. I'm probably wrong, but I'll give it a shot.
Puzzle canol and the shrine of courtesy (since you drown but don't drown)
The item, the silver sword (since you don't use it but give it to the dremora instead)
?