(18:20) Indeed, if they come to know of you, they will stone you or return you to their religion. And never would you succeed, then – ever.”
Muhammad Taqi-ud-Din al-Hilali and Muhammad Muhsin Khan,
(18:20) For if they come to know of you, they will stone you (to death or abuse and harm you) or turn you back to their religion, and in that case you will never be successful.
Mohammed Marmaduke William Pickthall
(18:20) For they, if they should come to know of you, will stone you or turn you back to their religion; then ye will never prosper.
Abdullah Yusuf Ali
(18:20) For if they should come upon you, they would stone you or force you to return to their cult, and in that case ye would never attain prosperity.
Mohammad Habib Shakir
(18:20) For surely if they prevail against you they would stone you to death or force you back to their religion, and then you will never succeed.
Dr. Ghali
(18:20) Surely in case they get the better of you, they will stone you or bring you back to their creed, and (then) you will never prosper at all.”
Ali Unal
(18:20) “Indeed, if they should find you out, they will stone you to death or turn you back to their way of belief and life by force, then you will never attain prosperity ever hereafter.”
Amatul Rahman Omar
(18:20) `(For) if they come to know of you they will condemn you or make you revert to their faith (by force) and in that case (that you revert to their faith), you will never attain your goal and prosper ever.´
Literal
(18:20) That they truly if they see and know of/overcome on you, they stone you, or they return you in (to) their religion/faith, and you will never/not win/succeed then ever (E).
Ahmed Ali
(18:20) If they come to know of you they will stone you to death, or force you to go back to their creed; then you will never succeed.”
A. J. Arberry
(18:20) If they should get knowledge of you they will stone you, or restore you to their creed, then you will not prosper ever.
Abdul Majid Daryabadi
(18:20) Verily they, if they come to know of you, would stone you or make you revert to their faith, and lo! then ye will never fare well.
Maulana Mohammad Ali
(18:20)-
Muhammad Sarwar
(18:20) they would certainly stone us to death or force us to follow their religion. Then we shall never be able to have everlasting happiness.”
Hamid Abdul Aziz
(18:20) Thus did We raise them up that they might question each other. A speaker from amongst them said, “How long have you tarried?” They said, “We have tarried perhaps a day or part of a day.” Others said, “Allah knows best how long you have been here. Now send one of you with this money of your s to the city, and let him look for the best food, and let him bring it to you that you may satisfy your hunger. And let him behave with subtlety (unobtrusively or with care and courtesy) and let no one perceive you (or let no one know about you).
Faridul Haque
(18:20) Indeed if they come to know about you, they will stone you or turn you back to their religion – and if so, you will never prosper.
Talal Itani
(18:20) If they discover you, they will stone you, or force you back into their religion; then you will never be saved.
Ahmed Raza Khan
(18:20) Indeed if they come to know about you, they will stone you or turn you back to their religion and if so, you will never prosper.
Wahiduddin Khan
(18:20) for if they find you out, they will stone you to death, or force you back into their faith. In that case you would never prosper.”
Safi-ur-Rahman al-Mubarakpuri
(18:20) For, if they come to know of you, they will stone you or turn you back to their religion; and in that case you will never be successful.
Ali Quli Qarai
(18:20) Indeed should they prevail over you, they will [either] stone you [to death], or force you back into their creed, and then you will never be saved.
Hasan al-Fatih Qaribullah and Ahmad Darwish
(18:20) For, if they appear in front of you, they will stone you to death or restore you to their religion. Then you will never prosper’
That is translated surah Al kahf ayat 20 (QS 18: 20) in arabic and english text, may be useful.