Valmiki Ramayana Ayodhya Kanda Sarga 37 Shloka 23
Original Shlokaन गन्तव्यं वनं देव्या सीतया शीलवर्जिते। अनुष्ठास्यति रामस्य सीता प्रकृतमासनम्।।2.37.23।।
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शीलवर्जिते devoid of good conduct, देव्या by the divine, सीतया Sita, वनम् to the forest, न गन्तव्यम् need not go, सीता Sita, रामस्य Rama's, प्रकृतम् present, आसनम् royal throne, अनुष्ठास्यति she will occupy.
You are devoid of good conduct, O Kaikeyi Divine Sita need not go to the forest. Remaining here she should occupy the royal throne of Rama.