Introduction: Demonstrating trustworthiness has been shown to increase trust and, in turn, information sharing in investigative interviews. However, the most effective ways to build trust in security contexts and the role of trust demonstrations in informant-handler relationships remain underexplored. This study tests the relative importance of competence, integrity, and benevolence demonstrations on initial trust development and willingness to cooperate in remote informant-handler encounters.Methods: Using a within-subject design, participants received background information on an organised crime scenario and listened to three simulated phone call recordings, where handlers demonstrated each of the three factors of trustworthiness during attempts to recruit an informant. After each recording, participants rated the handler’s trustworthiness and their own willingness to trust and cooperate and provided written feedback on each call. Participants also expressed their preferred trust-building strategy used by handlers and rated their trust propensity.Results: A repeated measures ANCOVA revealed no significant differences in willingness to trust based on the type of trustworthiness demonstration. However, trust propensity significantly impacted trust levels, so that more trusting individuals were more likely to trust the handler. Thematic analyses highlighted substantial individual differences in what participants liked and disliked about each approach.Conclusions: Findings suggest that no specific demonstration of trustworthiness is more effective in fostering initial trust, indicating that handlers should tailor trust-building strategies to individuals instead of adhering to general guidelines. Future research should employ idiographic approaches to further understand how individuals perceive and react to trust-building strategies.