Properly asserting legal capacity in court is not just procedural—it’s foundational. When representing a trust or estate, many plaintiffs unintentionally undermine their own cases by blending fiduciary roles with personal appearances such as “pro per” or “in propria persona.” This confusion often leads to dismissal—not because courts prohibit fiduciaries, but because the capacity is improperly stated. Courts cannot lawfully prevent a duly authorized fiduciary (such as an Executor, Trustee, or Attorney-in-Fact) from asserting rights on behalf of a trust or estate. However, when fiduciaries use personal language or appear to be representing a separate legal entity as themselves, courts may treat the filing as unauthorized practice of law. This article clarifies which capacities are lawful, which combinations to avoid, and how to protect your standing by appearing strictly in a private fiduciary role. In law, it’s not only what you say—but how you say it—that defines whether you are recognized with authority.