Translation of the verse 50 from Surah Al-haqqah : Number of verses 52 - - page 568 - Part 29.
And indeed it (this Quran) will be an anguish for the disbelievers (on the Day of Resurrection).
And indeed, it will be [a cause of] regret upon the disbelievers.
(69:50) and surely it will be a cause of regret for the unbelievers. *27
*27) That is, they will ultimately have to despair and regret as to why they had rejected this Qur'an.
Source : Al-haqqah Verse 50: And indeed, it will be [a cause of] regret upon the disbelievers.