Valmiki Ramayana Bala Kanda Sarga 68 Shloka 18
Original Shlokaदृष्टवीर्यस्तु काकुत्स्थो जनकेन महात्मना। सम्प्रदानं सुतायास्तु राघवे कर्तुमिच्छति।।1.68.18।।
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काकुत्स्थ: Rama, महात्मना by the illustrious, जनकेन by Janaka, दृष्टवीर्य: having proved the prowess (that Janaka), सुताया: daughter's, सम्प्रदानम् bestowal, राघवे to Rama, कर्तुम् to do, इच्छति is desiring.
Illustrious Janaka desires to bestow his daughter on the descendat of Kakustha (Rama) whose prowess he has witnessed.