The Messenger of Allah ﷺ said, "The signs of a hypocrite are three. When he speaks, he lies. When he is entrusted, he betrays. And when he promises, he breaks his promise."
أن رسول الله ﷺ قال: آية المنافق ثلاث: إذا حدث كذب، وإذا اؤتمن خان، وإذا وعد أخلف.
Bukhari narrated it in the Book of Testimonies (2682), and Muslim in the Book of Faith (59), both from Qutayba bin Saeed, who said, Ismail bin Jafar related to us, he said, Abu Suhayl Nafi bin Malik bin Abu Amir informed me, from his father, from Abu Hurairah, and he mentioned it. The wording given is that of Bukhari.