﴿ فَقُولَا لَهُۥ قَوْلًۭا لَّيِّنًۭا لَّعَلَّهُۥ يَتَذَكَّرُ أَوْ يَخْشَىٰ ﴾

“But speak unto him in a mild manner, so that he might bethink himself or [at least] be filled with apprehension.”

And speak to him gentle words for him to renounce such claims that perhaps he may be mindful be admonished or fear’ God and so repent — the ‘hope’ for Pharaoh’s repentance is expressed from their perspective for God knows that he was not going to repent.