Trust means betting one's actions on others' risky behavior. [definitional]
I agree with the emphasis placed by both Partha Dasgupta and Niklas Luhmann (in this volume) on the importance of personal agency in defining trust. Thus Dasgupta identifies trust as an expectation about another person's actions which influences our own actions before we have full knowledge of the outcome; and Luhmann exposes to full view the distinction between personal and impersonal social organization. Clearly trust is the predication of one's own actions on actions of others which bear an identifiable risk of turning out unfavourably.
DEFINE: Distills a definition of trust common to Dasgupta and Luhmann: acting on expectations about others before outcomes are known, accepting identifiable risk.
Diego Gambetta, Trust - Making and Breaking…, loc. 2424