A giant was roaming around the forest. It saw a hungry traveller shivering in the cold. The giant got sympathy and called him to his cave. On the way the giant saw the traveller blowing air through his mouth at his fingers. When the giant asked for the reason he replied that he was heating his hand by the air from his mouth. After reaching the cave, the giant served him a cup of hot soup. On receiving it, the traveller again started blowing air by his mouth at the cup. The giant was surprised and asked why he was again doing the same thing and whether the heat was not sufficient for him. But the traveller replied that he was cooling the soup then. Now the giant got suspicion and said, "You are blowing both heat and cool from your one and the same mouth. so I can't believe such a cheat. run away from here or else I will kill you." The giant chased him off. 
Nobody believes those who have dual word. 