Unless we are there to see an event for our own eyes can we always trust the source?
Where the evidence is provided, yes.
Scientific 'evidence' has been maniupulated over the years and spouted as fact. In fact, the very nature of science is to continue to change what it once saw as fact as more evidence and a wider perspective becomes clearer.
Manipulation is a strong word here. But again, if there is manipulation, that is provable which means the results of that are not fact.
Science doesn’t state fact unless it is incontrovertible and will not change. That doesn’t happen often. Science talks about theory. Evolution is a theory not a fact. Big Bang is a theory not a fact. Gravity is a theory not a fact. But the world is round, that is a fact that is provable.
Is the media always correct when they dish out one fact after another?
Only when they provide irrefutable evidence,
The BBC showed the funeral of Sir Jimmy Saville, who was buried in state. They stated as fact what a great man he was.
That is an opinion, not a fact. It is not something that is provable.
That you believe things to be facts when they are not, is why people are so confused about these things.