Valmiki Ramayana Ayodhya Kanda Sarga 9 Shloka 21
Original Shlokaचतुर्दश हि वर्षाणि रामे प्रव्राजिते वनम्। प्रजाभावगतस्नेहस्स्थिरः पुत्रो भविष्यति।।2.9.21।।
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रामे having Rama, चतुर्दश वर्षाणि for fourteen years, वनम् to the forest, प्रव्राजिते if banished, पुत्र: your son, प्रजाभावगतस्नेह: by affectionately winning the hearts of the people, स्थिर: भविष्यति will be firmly established.
If Rama is banished into the forest for fourteen years your son will be firmly established in the kingdom by affectionately winning the hearts of the people.