The word(s) "sincere" appears 5 time(s) in 5 verse(s) in Quran in Muhammad Pickthal translation.

(1) It is not righteousness that ye turn your faces to the East and the West; but righteous is he who believeth in Allah and the Last Day and the angels and the Scripture and the prophets; and giveth wealth, for love of Him, to kinsfolk and to orphans and the needy and the wayfarer and to those who ask, and to set slaves free; and observeth proper worship and payeth the poor-due. And those who keep their treaty when they make one, and the patient in tribulation and adversity and time of stress. Such are they who are sincere. Such are the Allah-fearing.

(2) And he swore unto them (saying): Lo! I am a sincere adviser unto you.

(3) Lo! We tested those who were before you. Thus Allah knoweth those who are sincere, and knoweth those who feign.

(4) The (true) believers are those only who believe in Allah and His messenger and afterward doubt not, but strive with their wealth and their lives for the cause of Allah. Such are the sincere.

(5) O ye who believe! Turn unto Allah in sincere repentance! It may be that your Lord will remit from you your evil deeds and bring you into Gardens underneath which rivers flow, on the day when Allah will not abase the Prophet and those who believe with him. Their light will run before them and on their right hands; they will say: Our Lord! Perfect our light for us, and forgive us! Lo! Thou art Able to do all things.