Rebbe Nachman of Breslev explains that emuna is like fertile soil - it makes anything grow. Indeed, emuna is the best medium in the universe for personal growth. Conversely, nothing grows well in bug or weed-infested soil. Stunted personal growth is virtually always the result of a lack of emuna.
Emuna gives a person the inner strength to fear no one other than Hashem. That's the greatest freedom in the world.
With the above in mind, we can describe emuna mathematically, as an equation:
Emuna = Growth + Fortitude