ظَنَّ and its 'sisters' are verbs that have a special effect on the nominal sentence when they precede it. They are called the verbs of affectivity.
When these verbs precede such a sentence, its subject مبتدأ and the predicate of that subject خبر are both put in the accusative case نصب and they are, then, called: the first direct object and the second direct object of that verb.
Example: زيدٌ صادقٌ Zaid is honest.
ظَنَنْتُ زَيـدًا صَادِقًـا \ I thought Zaid was honest. : زَيـدًاFirst direct object of ظنَّ. It is in the accusative case, with a Fatha at the end. صَادِقًـا : Second object of ظنَّ , it is in the accusative case with a Fatha at the end.
