Dependability is defined as being trustworthy and having one's back no matter what the circumstance is. Dependability is a very valuable trait to have in a leader.
Tom Brady is described as a dependable leader because he has shown that he can win the game with the time running down. The Patriots depend on him to make good throws in order to win the game for them. He stays on the job until it is done like a dependable leader would do.
These firemen display dependability because the owner of this house/building depends on them to put the fire out in order to salvage the house or building along with its belongings. They also depend on each other to do what their supposed to do in order to safely and effectively put out the fire.
This shot is an example of dependability. The team was depending on Austin Rivers to make the shot or else they would've lost the game. Rivers had the team's back and he made the shot to win the game for his team. His fans were depending on Rivers for the shot because it was a big game and they wanted to win. Austin Rivers came through for the team and won them the game.