The dwarves are let in.
A group of four dwarves, bearded and in dark clothes, brings in the ornate chest, setting it down while a fat, dwarf in colorful robes steps from behind them, clasping his hands.
"The weapon you requested in exchange for so-called 'doombox' has been finished." He looked at the guards, who opened the chest and handed him a cloth-wrapped weapon.
Unsheathed, the sword's handle gleams with the shinest bronze you ever saw. The blade's hilt is pure gold adorned with a large emerald in the center. The blade looks shiny and sharp, no doubt made from highest quality steel. Runes of dwarven kind are etched in the centre of the blade, running up to the tip, which seems to have been polished with some white metal.
The dwarven diplomat, humbly, approaches the throne and hands you the sword. You prepare for some heavy weight - but the thing is light as if it was a mere stick.
"The Blade of Puncturing, our smiths have called it. Albeit it might look like an ornate sword at first, the blade is hard enough to cut through chainmail, and the tip of the sword is capable of puncturing a thumb-thick layer of mithril." The dwarf clasps his hands and looks around.
"Now, where's the doombox? Our runemasters are eager to get their beards on it at last!"
A) "Doombox stays with me. Guards, get rid of these smelly bearded roaches!"
B) "Would you kindly consider the fact I do not wish to part with the doombox? Your runemasters would be welcome to come and do research here, in my palace."
C) "Well, a deal is a deal. My men will bring you the doombox."