Faith is a belief in something even though there is no evidence to prove the belief is legitimate. Many people have faith in god even though they have not seen or met this deity. When you have faith then you are confident in the outcome even though this can not be proven, you are acting on instinct rather than proof.
No man is a true believer unless he desireth for his brother that which he desireth for himself
Faith is believing in things when common sense tells you not to