This paper contributes to the discussion on persistency by addressing the enduring theological problem of certainty in faith, focusing on its interplay with trust, doubt, and ultimate foundation. The study revisits Eberhard Jüngel's understanding of certainty as an implication of trust, situating faith not as a static state but as a dynamic, forward-looking relationship with God. This certainty arises from God's act of addressing humanity, which reconstitutes the person and frees them from the need for self-justification. However, this liberating certainty does not exclude doubt; rather, doubt is recast as a manifestation of questioned trust, an enduring tension within the experience of faith. By examining the pitfalls of grounding certainty in a retrospective "ultimate foundation," the paper critiques tendencies toward theological fundamentalism. Instead, it emphasizes the eschatological orientation of Christian existence, suggesting that faith's certainty is rooted in the persistence of hope and the openness of "last things." These "last things," while inherently uncertain, persist as the horizon toward which faith is directed. Through this exploration, the paper aligns with the panel's broader inquiry into the nature of persistence, addressing how certainty, trust, and doubt endure as theological phenomena. It further reflects on the paradoxical persistence of both divine trustworthiness and human vulnerability, proposing a theological framework that integrates change, process, and the enduring nature of relational trust.