Trustworthiness is built through Credibility (your knowledge, expertise, and the confidence others have in your abilities), Reliability (your consistency and follow-through on commitments), and Intimacy (how safe and comfortable people feel sharing their thoughts or vulnerabilities with you).
These positive factors are then divided by Self-Orientation, which refers to how focused you are on yourself rather than on others. The lower the self-orientation (i.e., the more you are focused on others and their needs), the higher the trustworthiness.
This formula highlights that building trust is about not only proving your competence but also demonstrating that you genuinely care about others and are not purely self-serving in your interactions.