Trustworthiness - Security decision with respect to extended investigations to determine and confirm qualifications, and suitability to perform specific tasks and responsibilities.
NIST IR 7298
Trustworthiness - The attribute of a person or organization that provides confidence to others of the qualifications, capabilities, and reliability of that entity to perform specific tasks and fulfill assigned responsibilities. SOURCE: SP 800-79
NIST SP 800-39 Draft 2
Trustworthiness - A characteristic or property of an information system that expresses the degree to which the system can be expected to preserve the confidentiality, integrity, and availability of the information being processed, stored, or transmitted by the system.