If your assessment is that another person is untrustworthy, you’re giving yourself little choice than to be suspicious, watchful, checking always for many ways they are out to get you.
And when they encounter your suspicious watchfulness, and feel your uncertainty around them, they may well wonder whether you can be trusted. They become cautious, furtive, secretive around you, all of which produces exactly the kind of behaviour that seems to confirm your initial assessment.
Before you know it, a cycle of mistrust is created and sustained that may have had little foundation in either of you before it began.
In this way the assessments you make of others matter. Because when they’re untrue – when they are your ungrounded, unchecked suppositions – they have an uncanny way of coming into being simply because you’re making them.