Abu Hurairah (May Allah be pleased with him) reported:
Messenger of Allah ﷺ said, "There are three signs of a hypocrite: When he speaks, he lies; when he makes a promise, he breaks it; and when he is trusted, he betrays his trust."

[Al-Bukhari and Muslim].

Another narration adds the words: 'Even if he observes fasts, performs Salat and asserts that he is a Muslim".

عن أبي هريرة ، رضي الله عنه ، أن رسول الله ﷺ قال: “آية المنافق ثلاث: إذا حدث كذب، وإذا وعد أخلف، وإذا أؤتمن خان" ((متفق عليه)) .