When they say it should rain, it rains!
Satya Pratishtayam Kriyaphala Aashrayathwam|
Speaking the truth means, the speech happens with integrity of body, mind, intellect, words and being totally in the present moment. When one practices speaking with such integrity, then the person gets deeply rooted in Satya or consciousness, the essence of being. Whatever that person says will happen. The results of actions are in accordance with the will of such people who are rooted in the truth of being.
This is a Siddhi or an accomplishment of practising the Yama of Satya or integrity of communication. Sri Rama was a Satya Vakya or one who always spoke the truth. It is for this reason that all the kings of the Raghuvamsha never spoke much, because they practised this vrata or austerity of speaking only the truth. - Swahilya Shambhavi.