It makes for some heated discussions, because the same can be said for the opposite. If you know someone to never have lied to you, how do you listen to someone that claims otherwise?
How much do these examples change when the person who lied/didn’t lie was someone who was expected to always tell the truth by default?
This is where we are today.
Is the lie from a person, or an institution? Lies from people are fine and easy to forgive, though you may never trust the person again fully. However, when an institution (media, military, courts, police) lie there is no way to forgive as responsibility is diffused by so many people being in that institution such that there is no person to forgive. We forgive people, who don't forgive things.
Therefore, there is no forgiving an institution that lied to you, because you never know who was responsible, and therefore you can never trust them again. Ideally, the control of the institution that lied to you changes, then you may warily trust them again, at least provided that the same incentives to lie to you in the first place are not there (though they usually are). There has to be a distinct incentive to NOT lie to you.
It's actually easy to go through life with very little trust, because in most cases people or institutions either don't have to lie to you (there is no incentive to do so) or the incentives are to NOT lie to you.