The word of a Nobleman

Get the guarantees from Sivoyar Zablosky and Vladimir Zalesky than come back to Izbor Yavorsky.

It's not that easy, but at least it is clear what to do next.
Those willing to temper their weapons, should receive three guarantees from the nobles, who have to pledge their honor that they fully trust you, and that your weapons will never be brought against the government. The nobles have always feared rebellion in their own ranks. This never changed.
I'm noble, so I'll give my word, this will be your first guarantee.
You need two more. And I know who you should ask.
The first is Sivoyar Zablosky, the alchemists' trainer. You'll find him here in Novograd. Most likely, you'll have to earn his trust by completing a task.
The other is governor Vladimir Zalesky. He's at the camp in Oreshek, most surely he will make good use of your assistance.
When you have completed their tasks, do come back to me.