Will Allah accept the repentance of one who disbelieved in Him, trampled upon the Qur’an, and resorted to a sorcerer, knowing that he saw in a dream that his repentance was not accepted?

As long as she has repented to Allah with sincere repentance, then her repentance is accepted, Allah willing. And there is no significance to what she saw in the dream, because rulings of Islamic law are not built upon dreams. The important thing is repentance and adherence to the religion, and she must maintain her uprightness and stay away from the causes of disobedience.