The shaikh, Dr. Muḥammad ibn Ghālib Al-ʿUmarī, may Allāh protect him, said:

It’s been attributed to ʿUmar ibn Al-Khaṭṭāb, may Allāh be pleased with him, that he said: “I am not a misleader [or cheater of people], and no misleader [or cheater] can deceive me.”

The meaning [of his statement] is: I’m not a schemer or a deceiver, for these are defective, blameworthy characteristics, and I am not, likewise, one to be duped [so that] one [attempting] to deceive [me] might [succeed] in deceiving me or one [attempting] to scheme against me might [succeed] in scheming against me.

But despite that, a believer might [still] get deceived because his [own] heart is clear [of craft and guile in worldly matters] and because he’s good inside, [as] in the ḥadīth: “A believer is ingenuous and generous, while a shameless sinner is deceitful and despicable.”¹

¹rated ḥasan (good) by Al-Albānī; see Ṣaḥīḥ Sunan Abī Dāwūd, 4790 (tr.)

Source: twitter.com/m_g_alomari. 6 Jan 20.