I have a knockback II, fire aspect II, sharpness IV, unbreaking III diamond sword. I'll be willing to sell it to you when I get another sharp IV diamond sword so I can make the sword sharp V.
I'll notify you asap when I get a sharp IV sword to make this sword sharp V. Or you can give me a sharp IV sword and I'll have the price go down if you want to do that.
Once I get a sharp IV sword I'll also tell you my price.