وَٱلْخَـٰمِسَةُ أَنَّ لَعْنَتَ ٱللَّهِ عَلَيْهِ إِن كَانَ مِنَ ٱلْكَـٰذِبِينَ
Wa a lkh a misatu anna laAAnata All a hi AAalayhi in k a na mina alk ath ibeen a and the fifth time, that God's curse be upon him if he is telling a lie.
 - Mohammad Asad
and the fifth time calling down upon himself the curse of Allah if he is lying.
 - Muhammad Farooq-i-Azam Malik
and a fifth oath that Allah may condemn him if he is lying.
 - Mustafa Khattab
And yet a fifth, invoking the curse of Allah on him if he is of those who lie.
 - Marmaduke Pickthall
And the fifth (oath) (should be) that they solemnly invoke the curse of Allah on themselves if they tell a lie.
 - Abdullah Yusuf Ali