Answer:
To begin with, you must always bear in mind that the meaning of "true democracy" has seldom, if ever, been known in world governments, with a few exceptions. And definitely it has never been the form of government in the U.S. To some extent, U.S government has always had a form of "entrustment".
True democracy means that it is the people who truly govern, and it is the people who make the real choices, in a direct way, about how a government works. Cases like these are seen in some countries in Latin America, and in Europe, like France, where the people have direct say on the choices made by direct elections of rulers. There are no "intermediaries", or if they are, they are directly elected and are bound by the decisions of the people through such means as referendums.
But in the U.S, this is not the system of government. The U.S uses a form of intermediate democracy in which, the people have a say in government by electing intermediaries, or representatives, who will in turn be the ones to choose in the end. So in the end, the U.S uses a form of "entrusting" that has worked for the country pretty well, however it might have been altered through the centuries.
Given this, to answer your question: Is the democratic form of government the only means to preserve freedom, or can government be entrusted to representatives, then the answer is, provided some limits that democracy does provide, intermediaries are not always a means to limit freedom. The U.S is one of the best examples. Britain is also an example. Through a system of constitutional monarchy, British people enjoy great freedoms thanks to a monarchical rule that has been placed within boundaries through a constitution that is the result of democracy.
