Yusuf Ali
Nay, were ye to know with certainty of mind, (ye would beware!)

Sahih International
No! If you only knew with knowledge of certainty...

Shakir
Nay! if you had known with a certain knowledge,

Pickthall
Nay, would that ye knew (now) with a sure knowledge!

محمد جالندھری
دیکھو اگر تم جانتے (یعنی) علم الیقین (رکھتے تو غفلت نہ کرتے)