Valmiki Ramayana Sundara Kanda Sarga 55 Shloka 26

यद्वा or if, सर्वत्र everywhere, प्रभुः lord, अव्ययः that which never fails, अयम् this, दहनकर्मा burning firegod, मे my, लङ्गूलम् tail, न दहति has not burnt, आर्याम् noble Sita, कथम् how, प्रधक्ष्यति will he burn.

'If not so, the firegod who never fails in burning has not burnt my tail. How will he burn noble Sita?'