OP. What is your citizenship? The easiest would be Canada. Developed countries like the UK/Germany/France are a bit harder to obtain financing from. Any country not on this list you're SOL (sh** out of luck)
You can try gofundme.com
THIS^^^^^^. If you are not a citizen, cannot self-fund, cannot obtain financing from your home country, or cannot get a US citizen to co-sign for your private loans, you are very likely going to be SOL.
I have never heard of a "trusted lender," other than maybe a school itself, that will extend unsecured financing, for an education or for anything else, to a foreign national. The risk of default is simply sky-high due to the uncertainty involving your immigration status and the near impossibility of securing repayment if you leave the country.
As was said above, you really should have worked this out before you went to all the trouble of applying, since, as you are now learning, things like this don't just work themselves out. The fact is, the school likely won't even allow you to enroll without proof of funding, unless they are giving you a full ride scholarship. Good luck!!!