In a Leap of Faith, why does Sam consider it a leap of faith to do the diving board from the platform?

He had to leap and do a very difficult dive from a high up diving board and when his cousin was shouting at him a flashback came back to him. He leaped off and he hit the water and he came up and he wiped the water from his eyes and he turned to see his cousin giving a thumbs up sign to the coach and he knew he had made the team. He felt very proud and he knew that jump was a leap of faith because he had finally jumped from the high dive and made the diving team.