The US buyer's first question is often: who else do you sell to? A properly packaged reference answers before the question is asked.
It does not have to be a Fortune 500 client. Three things count for the US buyer: whether someone like them already trusts you, whether you have exported beyond your home market, and whether you can show consistency rather than a one-off transaction.
Scandinavian clients are an excellent reference: in the USA, the Nordic demand for quality is read as a quality mark in its own right.
A short case in one page or three sentences: the client and country, what we supply, for how long, and one number, for example delivery accuracy or volume. Named with permission, anonymous without it, in the form "a leading Swedish furniture manufacturer".
Put the references where they are seen: a line under your email signature reading "trusted with our goods by", in the header of the price list, on the product card. Do not wait to be asked.
With your first US client, sell the process: factory certificates, quality system, the owners' background, and offer a low-risk start such as a small trial batch with strict inspection. Honesty works: "we are new to this market and that is why we try harder" beats bluffing.
The first consultation is free: together we'll see who in the US already buys your product and how to reach them.