إِنَّ جَهَنَّمَ كَانَتْ مِرْصَادًا
Sentence structure
إِنَّ emphasizes the statement. جَهَنَّمَ is its noun, and كَانَتْ مِرْصَادًا is its predicate clause, describing Hell as a place lying in wait.
إِنَّ — indeed
Grammar: A particle of emphasis resembling a verb; it makes جَهَنَّمَ accusative.
جَهَنَّمَ — Hell
Grammar: A proper noun in the accusative case and the noun of إِنَّ. It is diptote ممنوع من الصرف.
كَانَتْ — has been / is
Grammar: A third-person feminine singular perfect deficient verb. Its noun is the understood هِيَ, referring to Hell.
مِرْصَادًۭا — a place lying in wait
Grammar: An indefinite accusative masculine noun and the predicate of كَانَتْ. The whole كَانَتْ clause is the predicate of إِنَّ.