The most reliable methods for discerning truth have always been those that relied on reason, rather than on any inward sense of what is true or false. Thinking something is true merely because it "feels true" is a nearly certain way of being taken in and made a sucker. Reasoning your way to the truth is much more reliable.
However, reasoning is still very much imperfect. It is fraught with cognitive biases and other pitfalls. Like someone who has only a hammer with which to drive screws, we are a bit like a person forced to use a tool (reason) that is not perfect for the task assigned to it (discerning truth).
Obviously reason did not evolve purely for the purpose of discerning truth, but for some other purpose.
I rather favor Hugo Mercier and Dan Sperber's hypothesis that reasoning evolved in our species of great ape in order to help us (1) persuade others to help us, and (2) to help us figure out when someone is likely lying to us or likely telling the truth. Notice there is a subtle distinction between discerning the truth and discerning when someone is telling the truth. Reason evolved for the latter function, rather than the former. In practice, that means it evolved along with all sorts of cognitive biases and other imperfections that would presumably have been weeded out if it had evolved solely to discern truth.
An implication of Mercier and Sperber's hypothesis is that we reason best when our reasoning is "peer reviewed" so to speak, because we are quite often blind to our own biases, etc, but not as much to other's biases.