Since you have located History SE on the Internet, one approach would be to ask here
I have read an account of a particular event X from a source Y
"Is the account true of false?"
in the cases for which a historical account has particulars that are
still not known
Again, you can ask the question here. That does not mean that the particular question can or will be settled here to any particular observer's complete satisfaction.
Some historical questions do not involve controversy, for example, "On what date was the United States Declaration of Independence signed?".
Other historical questions might not ever be entirely resolved, even using modern technology, to any or all readers, students, authors of history complete satisfaction, for example, the questions of the origin of the Ancient Egyptians and the claims of certain people having "deciphered" or "transliterated" the so-called "hieroglyphics" of Ancient Egypt.
To illustrates the basic issue of citing and relying primary evidence and then setting historical questions aside, some people might live a number of years believing that their parents are their biological parents before being told, or discovering themselves, they were adopted, or, that one of their parents is actually not their biological parent. Since no human remembers being born, the child has only the account of their parents to rely on, or, when they reach a certain age, the ability to cite a birth certificate. However, if the child is never told that they were adopted, or one of their parents is not their biological parent, then they could easily live their entire lives without ever questioning the primary source of a birth certificate being true or that one or more of their parents is not their biological parent.
There is also the element of instinct involved in the investigation and study of history, which should not be discounted entirely, else one might not investigate paths to the truth that do not appear in a previously published work, but rather, spring from your own intellect. At some point an individual might become enlightened to the degree that they draw their own conclusions based on their own reasoning. The important point to remember at that stage is to clearly state that you have drawn your own conclusions, and attribute the conclusion to yourself. Facts can be disputed and conclusions drawn refuted. History is a living art and science. Whether you stand on the conclusions that you draw, whether supported by a primary or secondary source, is your own prerogative.
Cannot honestly state that History SE is absent of institutional flaws, users which have disclosed or un-disclosed biases, or that even sources cited will not be questioned. Though History SE is at least here and available to vet questions such as "I have read an account of a particular event X from a source Y "Is the account true of false?"".