Valmiki Ramayana Sundara Kanda Sarga 21 Shloka 6
Original Shlokaनाहमौपयिकी भार्या परभार्या सती तव।।5.21.6।। साधु धर्ममवेक्षस्व साधु साधुव्रतं चर।
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परभार्या other's wife, सती chaste, अहम् I am, औपयिकी obtained by efforts, भार्या wife, न not, धर्मम् righteous, साधु properly, अवेक्षस्व you may examine, तव your, साधुव्रतम् honesty, साधु honest, चर you may practise.
"I cannot be your lawful wife obtainable by your personal efforts. I am a chaste woman married to another man. (Being a king) examine the dharma honestly and adopt a pious way of life.