From the bottom it looks easy, but once you're about to jump, motivation and willpower drops, your reptile brain resists. You become scared, really scared.
When you tell others and yourself you can do something; Do you really mean it?
If you are able to do something, lets say, jump off the cliff. But you are lacking willpower, are you actually able to do it? - I think not.
You can only do something if you have all that's necessary to do it. This includes the willpower. And the only way to find out if you have the willpower is to go out and actually do it.
Take a dive. Challenge your fears. - One you're underwater, in a new reality, you can't wait to do it again.