1) Credible–worthy of belief
2) Verified–demonstrated truth.
There are all sorts of evidential lines that lend credibility and have nothing to do with veracity. The only thing that makes veracity is correspondence to reality (correspondence view of truth). One can approximate verifications with partial demonstrations, but in the absence of scientific-type experimentation (which is largely impossible for historical events), 100% verity is rare. Usually what people deal in is credibility where the witnesses and circumstances are shown to have endured several or relevant filters that can undermine credibility–such as family/friend bias, monetary interests, personal gain, inadequate reporting, contradictory reports, rescensions, etc.
For example, suppose Barney’s alcoholic mother was in the bathroom drinking when an intruder came into the house, grabbed Barney’s gun from the drawer (after Barney lunged for that drawer), said, “Give me all your money or I’ll kill your sister over their [the one cowering in the corner].” Barney refuses, the sister gets shot and killed, and the intruder leaves. Now Barney and the mother are the only living witnesses. Barney is obviously biased, and his testimony, for all that it is worth, is not necessarily the most credible witness, especially since it is discovered in court that Barney always hated his sister and had threatened bodily harm to her several times when she disagreed with him. Likewise, barney’s mother has low credibility because she’s biased, was in the bathroom, and is drunk most of the time because of her severe alcoholism. She’s about to lose her only remaining child to jail, so she’s not the strongest witness.
Do any of those threats to credibility undermine veracity? No. Low credibility witnesses can still tell the truth. Concurrently, high credibility witnesses can still tell lies. Credibility is merely a measure, often imprecise and partial, of whether a person has strong reasons to tell the truth, or few/no strong reasons to lie. Plus, there is still the chance for misreporting–telling what one thought was true, but is not.
Several evidential tests we use fall within the “credibility” category such as 1) multiple attestation, 2) diverse attestation, 3) embarrassing attestation, 4) complementary attestation. To approach verification we need other circumstantial and material evidence which shows that the report in question is the only reasonable or the best account of an event. Material and circumstantial evidence, in this case, might be dusting for prints on the gun, the shoe prints on the door that the intruder kicked in, tire tracks on the dirt drive-way that don’t match the family’s cars, etc. For a biblical event, we can weight witnesses against each other all day long–OT reports versus ANE reports outside of Scripture. But we also need archeology, geographical analysis, cultural anthropology and so on to show whether an event actually happened, rather than simply showing that, “This witness had no reason to lie, but could still be accidentally misreporting an event.”
A problem that soon arises, though, is that this “guilty until proven innocent” approach to ancient reports is too cumbersome to do on wide scale or consistently. Historians, and our court of law, routinely circumvent that skeptical standard with an alternative credulity principle, namely, evidence and witnesses are considered truthful/innocent until proven false/guilty. This is not at all a verification principle since the principle would have to assume the truth of all isolated witness reports (i.e., where something is claimed which cannot be falsified or verified externally). It is however a functioning credulity principle that serves to avoid the endless downward spiral of historical skepticism, Jesus-mythicism, and deconstructionist histories. This historical credulity principle works well with reliabilism (i.e., our senses are generally reliable), realism (i.e., reality is knowable), and the epistemic credubility principle a la Richard Swinburne (i.e., what seems to be true probably is true, unless demonstrated otherwise).