Authenticity

From Rich Diviney's book The Attributes: 25 Hidden Drivers of Optimal Performance.

Among all of the leadership attributes, authenticity is the most important for building trust.

Authenticity, by definition, can't be faked. It can't be copied: There's not template, no checklist of external behaviors or attitudes that are the model of authenticity. Being firm and taciturn doesn't make one any more or less of a leader than being easygoing and funny. What matters more is whether that person is authentically firm or authentically easygoing.

The simplest measure of authenticity is consistency: consistency of action, consistency of thought, consistency of values. Consistency builds trust, and a lack of consistency instills doubt. Think of it this way: If stepping on the brake pedal didn't consistently stop your car - if sometimes it made the engine race or turned on the wipers instead - you wouldn't trust the brakes, right? The same idea applies to humans. If you don't believe you're seeing authentic versions of people, if you suspect they are play-acting or pretending, presenting insincere facades that shift with their audience or their own whims, it's impossible to build an honest foundation of trust.

To make it even simpler: Authentic people are genuine. They aren't markedly different in private than they are in public.