Vulnerability is not weakness—it's the foundation of all courage. Brené Brown, bestselling researcher on human connection, explains why we armor ourselves against emotional risk, how betrayal slowly erodes trust through disengagement, and why self-trust is the prerequisite for meaningful relationships. She reveals the four measurable skill sets of courage backed by 25 years of research across 165,000 people in 45 countries. Courage requires vulnerability; without uncertainty, risk, or emotional exposure, brave action is impossible, as confirmed by both Special Forces soldiers and NFL players.