Seems to me your boss hasn't got a clue about today's best practices in what concerns business. He will ultimately cost you, himself and the company not only this one deal, but what is called Customer lifetime value, which can amount to a fortune.
That said, you are not in a position where you can do anything about this. All you can do is tell your boss that you disagree with this course of action and make a formal reccomendation (written) that the client be sent a sample. You will obbey what he says of course, but after all is put to writing, you have covered your back and can have a clear conscience.
The main source of problems with samples shipping in North America is FRAUDS. I am a Canadian buyer and believe me when I say this. Lots of purchases made over the internet turn-out to be fraudulant.
I am now making a purchase of $800 US including shipping and I am asked to send the money to an individual in Cina because Western Union won't send money to a company. Just think abot this. I am asked to send money to an individual I do not know and as we are told, chances of recuperating my money if things goe's wrong, my chances are "0".
On the other hand, if the north American buyer doe"s not fulfill his part of the bargain, it won't be long before the police comes knocking on my door. It's all about laws and population. Looking for a theif in a 35 millions population is far easyer than for a country that has a population of over 1 billions.
The risk is therefore much more important on us, Canadian buyers while you're risk is minimal. and all you will loose is a potential large customer and future sales. It is also easy for you to check the solvability of a customer while it is impossible for us to do so.
The main issue here is trust and trust has to be acquired by proper bussiness practice.