الَّذِينَ يَظُنُّونَ أَنَّهُم مُّلَاقُو رَبِّهِمْ وَأَنَّهُمْ إِلَيْهِ رَاجِعُونَ
Allazeena yazunnoona annahum mulaaqoo rabbihim wa annahum ilayhi raaji'oon
those who are certain they will meet their Lord and that to him they are returning.
Yaẓunnūn ordinarily means to suppose or think likely, and commentators observed that here it has to carry settled certainty instead. The same verb returns thirty verses later in this surah, where it names people who only guess, so one word holds both confident knowledge and idle conjecture. What separates them is the object: what is expected, and on what grounds.