Task: Classify the mental state of the tweeter based on the tweet, determining if it is 'neutral or no emotion' or characterized by any of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust).
Tweet: A good head and a good heart are always a formidable combination.' - Nelson Mandela
This tweet contains emotions: 
optimism, trust