Surah Al-Jaathiya, Verse 32
وَإِذَا قِيلَ إِنَّ وَعْدَ ٱللَّهِ حَقٌّۭ وَٱلسَّاعَةُ لَا رَيْبَ فِيهَا قُلْتُم مَّا نَدْرِى مَا ٱلسَّاعَةُ إِن نَّظُنُّ إِلَّا ظَنًّۭا وَمَا نَحْنُ بِمُسْتَيْقِنِينَ
Translation — Sahih International
And when it was said, 'Indeed, the promise of Allah is truth and the Hour [is coming] - no doubt about it,' you said, 'We know not what is the Hour. We assume only assumption, and we are not convinced.' "
Source
Kur'an-ı Kerim, Câsiye Suresi 45:32
https://kuran.diyanet.gov.tr/mushaf/kuran-meal-2/45-suresi-32-ayet