This study focuses on the context of AI-generated content (AIGC) advertising, aiming to investigate how two typical disclosure strategies—technical disclosure and relational disclosure—influence user trust through the mediating roles of informational authenticity and expressive authenticity, while further examining the moderating effects of AI appreciation and advertising appeals. Through multiple scenario-based experiments, a moderated dual-mediation model was developed and validated. The results showed that technical disclosure primarily built trust by enhancing informational authenticity, with this effect being more pronounced among users with high AI appreciation and in the context of informational advertising appeals. In contrast, relational disclosure fostered trust mainly by strengthening expressive authenticity, proving more effective for users with low AI appreciation and in the context of emotional advertising appeals.