"Believe in yourself! Have faith in your abilities! Without a humble but reasonable confidence in your own powers you cannot be successful or happy"

This quote by Norman Vincent Peale emphasizes the value of having self-belief and confidence in one's abilities. It recommends that such self-assurance is required for accomplishing success and joy. Using the word 'simple' indicates that while it is necessary to have confidence, it should not be extreme or big-headed. Instead, it needs to be grounded in an affordable evaluation of one's own abilities. Overall, the quote encourages individuals to rely on their own capacity and to believe that they can achieve their objectives.