of our tendency as human beings to operate from expectations - the expectation of predictability in anyone's behavior is about keeping the relationship within our comfort zone.

Seems to me that a trusting character and the emotionally healthy trusting relationships that result can only be created in a context of commitment and sincere intention on the part of both parties in a relationship to each other and perhaps even to a shared future.  Commitments are a much better truing mechanism than expectations when things don't go as planned and give us a foundation from which to recover and build from the disappointments rather than to reinforce the fear of trusting others like it were a hot stove we now "know" not to touch again.