The Prophet ﷺ said, "The signs of a hypocrite are three: 1. Whenever he speaks, he tells a lie. 2. Whenever he promises, he always breaks it (his promise ). 3. If you trust him, he proves to be dishonest. (If you keep something as a trust with him, he will not return it.)" (Using translation from Bukhārī 33)
"آيَاتُ الْمُنَافِقِ: مَنْ إِذَا حدَّثَ كَذَب، وَإِذا ائْتُمِنَ خانَ، وإِذَا وَعَدَ أخْلَفَ".