Valmiki Ramayana Sundara Kanda Sarga 54 Shloka 4
Original Shlokaदुर्गे विनाशिते कर्म भवेत्सुखपरिश्रमम्। अल्पयत्नेन कार्येऽस्मिन् मम स्यात्सफलश्श्रमः।।5.54.4।।
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दुर्गे the citadel, विनाशिते if destroyed, कर्म labour, सुखपरिश्रमम् happy conclusion, भवेत् will be, अस्मिन् in this, कार्ये in the task, अल्पयत्नेन with some effort, श्रमः labour, सफलः successful, स्यात् will be.
'If the citadel is destroyed it would be a happy conclusion with a little effort. I can successfully complete my task.