Valmiki Ramayana Sundara Kanda Sarga 55 Shloka 28
Original Shlokaतपसा सत्यवाक्येन अनन्यत्वाच्च भर्तरि। अपि सा निर्दहेदग्निं न तामग्निः प्रधक्ष्यति।।5.55.28।।
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तपसा by asceticism, सत्यवाक्येन by adhering to truth, भर्तरि towards her husband, अनन्यत्वाच्च completeexclusive devotion, सा she, अग्निम् fire, निर्दहेत् अपि may even burn, ताम् her, अग्निः fire, न प्रधक्ष्यति is not capable of burning.
'By virtue of her power of asceticism, power of truthfulness and exclusive devotion towards her husband, she may consume the fire. Fire will not burn her'.