व्यतरद् भागिनेयाय सुतां कुर्वन् स्वसु: प्रियम् ॥ २३ ॥
sutāṁ kurvan svasuḥ priyam
Though Rukmī always remembered his enmity toward Lord Kṛṣṇa, who had insulted him, in order to please his sister he sanctioned his daughter’s marriage to his nephew.
The answer to King Parīkṣit’s question is given here. Ultimately Rukmī approved his daughter’s marriage to Pradyumna in order to please his sister, Rukmiṇī.