فَانْفَتَحَتْ لِلْفَرَحِ قُلُوبٌ طَالَ انْتِظَارُهَا.
Then hearts long burdened by waiting opened in joy.
The hearts are pictured as opening like a physical enclosure. The intended meaning is emotional relief, not a literal anatomical event. Infaṭaḥat makes that change vivid and sudden.
The image also echoes the door just reached in the story: external arrival is followed by an inward opening. Their thematic correspondence does not make the words a case of paronomasia.