We quite often homogenise the idea of trust, not noticing that issues of trust can be very different. Trusting a person in general is not the same as trusting a person at a specific time or for a specific event, and trusting a person is different than trusting their judgment, their taste, their skills, their luck, or something more specific than simply them as a whole.
“Don’t you trust me?”
Many people are offended when they think that someone does not trust them, as if it reflects poorly on them as being untrustworthy. This is a misconception of how trust is applied; if someone does not trust you, it does necessarily mean that you are not honest and genuine, it could instead mean many other things that have nothing to do with your character.
The idea of “trustworthiness” as a defining character trait is far too broad to be meaningful in general. Very few people if any are entirely trustworthy or untrustworthy; instead they can be trusted depending on the situation, sometimes more reliably than others.
Instead of thinking of trust as a very general characterisation, we should apply it when it make sense. We should trust when we are certain enough of something, not based on assumptions and generalisations. While you may feel like you trust someone in general, such as a parent, that trust is mistakenly general. What you might actually trust is for them to not lie to you, or for them to do what is in your best interest, but that does not mean that you trust them to do very specific and difficult things. If your parent knows nothing about electricity or circuits, then you should not trust them to wire a house, no matter how much you feel like you trust them otherwise.
As that example shows, you should trust based on reason, not based on arbitrary generalisations or rules. You trust a parent not to lie to you only if you have reason to believe that. If your parents believe that lying to you is better than hurting you with the truth, or if they think innocent or harmless lies are OK, or if they are compulsive liar, or if they do not care about telling you the truth, then it is very possible for your parents to lie to you. If you claim that your parent would never lie to you, you have to ask yourself if there is really absolutely no situation in which they would. Even someone who despises lying, or has promised to never lie to you might decide it is better to lie in some situations, such as under duress, or when forced to or when it is the best choice available to them. To say one person is trustworthy and another is not, without any other context, is therefore imprecise.
We trust an electrician to be able to do electrical work because they have the knowledge and experience to do so. We trust someone who cares for us to try to help us, because if you care about someone you want the best for them. We trust someone to tell us the truth if they want us to know the truth.
It does not make sense though to expect someone who cares for us to do what is best for us, unless they have the judgment, information, and ability to both know and do what is best. Merely caring about someone does not mean they will not make mistakes, or do what they think is best for you rather than what you think is best or what is actually best. We don’t trust our parents to fix a car unless they know how to. If we merely trust them because we know they want to help, then they can create more issues due to their lack of knowledge on car mechanics, and even break the car even more. This means that we should not trust people to do something if they haven’t earned that trust for that thing.
Trust is not a reflection of character necessarily. While trust is rarely if ever completely certain, we judge when we are certain enough to risk trusting someone. Trust is necessary for many things, and someone we have to trust people without sufficient information, but in such cases we make the best decision we can at the time. This is why we must be clear on what trust is and what it is exactly that we are trusting. While you may not trust your enemy (to tell you the truth), you might be able to trust them to tell someone else the truth, or you might trust them to follow their own code. You may trust your friend to try to help you, but you might not trust them to make the right decision in how to help you, which can lead to them making things worse.
We shouldn’t judge people as a whole, or even simply judge their honesty or character, based on individual instances where we cannot trust them. Instead we should simply judge the specific situation in question: if they will be honest, if they will do what they say, etc. Trust is a matter of attempting to predict the future actions of people, and thus allowing them to act on their own. As a predictive matter it is important to not leave it to chance by simply choosing who to trust based on whether or not you feel betrayed by someone or because you feel you’re supposed to trust them.
Trust people when you have reason to believe they will, not when you think you have to trust them.