He may also not trust the dwarf because due to lack of charisma he seems suspicious to him, So who would guarantee that dwarf wont just steal the goods and will never be seen again.
Which is why I say limit high-ish ocr people to the less valuable jobs. (at least until they prove themselves)
I realize that barovians are xenophobic, but I feel like not dealing with high ocr peeps makes more sense in the more "down to earth" jobs. (like the fishing dock worker occupation that was just added) It seems odd to me that my dwarf has a regular working relationship with the trade guy (Thord makes boots and bags for him) but he won't trust my dwarf to carry mining equipment up to Dvergeheim.
ICly, I guess I just have to accept that the trade guy is a typical xenophobic barovian. He'll buy stuff off of my dwarf, but he doesn't trust him out of his sight with anything valuable.
(train of thought action)
What if the trader let high ocr people do the jobs, but made them leave "collateral" with him. (aka a 100g delivery mission would require a 50g deposit in order to accept the job) Make the collateral scale down based on how low your OCR is, with "normal" ocr levels only requiring like a 5g collateral. Native characters would straight up not require any collateral to help drive home the xenophobic nature more. (I am reminded of the Ogre DM event during the new character week, where we got the barovian PC to haggle with the ox-seller to get a deal on the herd)