Satya is “action of mind and the use of speech in the spirit of welfare”. It means to tell the truth and act in a straightforward and honest way which will promote the welfare of all. The root 'Sat' means what does not change, what is eternal. And the word itself - adherence to absolute truth. So if you achieve the verity on human level being then you may comprehend the Supreme Verity (spiritual reality, eternal and unchanging), the harmony with it, the live energy from it.
Satya is not only about ascertaining the facts and truth, it has more wider meaning. It also means to become completely like a Supreme being in using our speech and intelligence. The characteristic of Supreme being is love. So need to use our speech and intelligence with love, in the spirit of benevolence.
--- With what difficulties you may encounter? --- In some conflict situations the straight truth (when you have conflict between the truth as a statement of facts and benevolence) may be the cause of degradation, loss of inspiration, suffer for other beings. So avoid it. From the other hand, feel the truthfulness inside yourself, feel the difference when you are going to tell a lie because of selfish interests. Analyse your motives, ask questions to yourself (Why I am telling it? For what am I doing it? Am I moved by fear? Am I act because of prestige?..). Your motives should be clear, wise and benevolent. Otherwise you will break the principle of Satya. Once again, in cases where telling the exact truth will harm others, then Satya means to say what is best for the welfare of others rather than to tell the exact facts. Adherence to Satya brings about tremendous strength of mind and is extremely important for spiritual success.
--- Benefits --- Satya is straightens the intellect. When your are thinking honest, speaking honestly, doing honestly then you act confident, you feel how the energy goes through your thought, body and words. Your actions are gaining especial power/energy.
--- How to practice? --- 1. Cultivate the truthfulness in your thoughts (at least for yourself for beginning). Do not try to excuse/justify yourself. Admit things as they are. Note! Think twice before tell something to others. Ask yourself simple question - Will my words be benevolent regard to others and for me? Benevolent means the progress (development, improvement, harmony with supreme reality) on mental and spiritual levels as well! 2. Always try to make your speech in a way to inspiring, enchanting people around and yourself. Avoid non-constructive criticism. 3. Cultivate positive thinking. Avoid complex of pessimism, inferiority, superiority.
--- Definition --- https://www.yogapedia.com/definition/5354/satya