Trust is not so black and white as you seem to be making it out to be.
When I go through an intersection in my car when the light is green, I trust that the car traveling cross-traffic from me will stop when his light says red. Do I know it’s possible he may not, sure. Still, I trust that he will, or I would not go through the intersection.
In marriage, trust is absolutely essential to the bond between husband and wife. But at the same time, we always know it’s possible for the spouse to let us down in a small way or a very big way. Yet still, we trust that they will do what they have promised to do by entering into the marriage covenant.
Trust in God is an absolute trust. It is a complete abandonment to God taking care of you and your adherence to what God has promised and revealed to his creatures.
Placing our trust in people is never a sure thing, yet still we do it, and it’s a reasonable thing to do when done with wisdom and prudence.