There’s different kinds of trust in different ways.
A crucial life skill is not “knowing whether to trust or not trust”: that is FAR too vague of a grouping.
Rather it is knowing IN WHICH WAYS can I trust this person (to have my interests and goals in mind) and in which ways can I NOT fully trust this person (to have my interests and goals in mind).
So for example: Most of your non-allies won’t murder you in cold blood.
So you can probably trust most of your non-allies in that way: They will probably not murder you in your sleep.
Already there is some measure of trust with non-allies most likely (exceptions happen of course)
Likewise, if there are power differences between people that cannot be FULLY equalized (parent / child, boss / worker, authority / citizen), there are going to be SOME areas which there may be silence.
In those areas, it may be something that is fragile: a preference or taste that the more powerful figure will likely disapprove of and so therefore the lower power will be silent about – or possibly lie when confronted – because they are protecting it.
For the powerful, they may omit “the whole story” because it could be too much for the less powerful to bear all at once: they are not in the same positions and may not want to know all of the things in all of the details at this time – and it may not be necessary.
But secret friendships, well, that can be another story altogether.====