If we ever feel betrayed by somebody whom we trust, it is our own responsibility. We cannot be angry or blame that person for being unreliable.
The point is, we don't have to trust anyone. We don't have to not trust anyone also. But we deal with everyone as they are, not because how they were in the past, or how they will be in the future.
When we trust somebody, that is because we trust ourselves, to allow ourselves to trust that person. And when that person betrays our trust, we are disappointed by our own trust towards ourselves, not because that person is not reliable. It is our own responsibility to take the risk to trust someone and expect that person to be reliable.
If we truly want to rely on something, it will be only ourselves. And sometimes, or most of the time, we can't even trust ourselves (the one who we think we are). And so, free ourselves from this word 'trustworthy' or 'reliability', or expect ourselves or other people to be 'reliable'.
Before we know our true Self, we don't even know if this true Self exists or not, as we are ignorant. The thinking mind can't perceive something that is nameless and formless, without qualities, beginningless and endless. Just like the mind sees things through the eyes, but the eyes itself doesn't see, or it couldn't see the mind. The mind exists, but only when it is being aware of itself. If the mind is not aware of itself, then whatever the mind perceives through the senses, it takes the name and form of the objects of the senses. The mind becomes what it perceives. That's why the nature of the mind is forever changing and restless.
And so, we can't say to ourselves, "Trust ourselves", as this 'ourselves' who we think we are, is the thinking mind. It is impure, impermanent and will change. How can we rely on something that is always changing and not pure? We will only hurt ourselves if we rely on 'ourselves'. But, when we realize our true Self, beyond the thinking mind, that is not subject to impermanence of the qualities of names and forms, then we can say, "Trust our Self", or "Surrender to the higher Self", as this Self is unchanging, uncontaminated by the ignorance or impurities in the mind. It is beyond what our mind believes as good and bad, reliable or unreliable.