The rise of financial influencers, or fin-influencers, has transformed how younger audiences, particularly Gen Z, engage with investment-related information. This chapter develops a conceptual framework to examine how fin-influencers shape investment willingness through two key psychological pathways, user engagement and perceived trust. Drawing from Source Credibility Theory, Parasocial Interaction Theory, Narrative Transportation Theory, and Prospect Theory, the model explains how influencer characteristics, financial credentials, communication style, parasocial interaction, and storytelling style contribute to these mediators. The framework also incorporates perceived risk as a moderating factor that can strengthen or weaken the link between engagement, trust, and investment willingness. By articulating twelve core research propositions and two moderating relationships, the chapter extends existing theory into the digital financial communication context and offers directions for empirical validation. The discussion emphasizes the evolving nature of financial authority, where relatability, emotional connection, and narrative framing often rival formal expertise in building influence. Theoretical contributions lie in the integration of communication, behavioral finance, and psychology to explain investment related decision-making in online spaces. Practical implications span content creation, platform governance, financial education, and industry partnerships, highlighting the need for ethical, transparent, and context-aware communication strategies in the growing domain of influencer-led finance.