Valmiki Ramayana Sundara Kanda Sarga 37 Shloka 10
Original Shlokaमम प्रतिप्रदानं हि रावणस्य न रोचते। रावणं मार्गते संख्ये मृत्युः कालवशं गतम्।।5.37.10।।
1 source checked for this shloka
मम my, प्रतिप्रदानम् returning, रावणस्य to Ravana, न रोचते is not liked, कालवशं गतम् fallen into the trap of time, रावणम् Ravana, संख्ये in a battle, मृत्युः death, मार्गते is searching.
"Ravana did not like to return me having fallen into the death trap. Death lies in wait for him in battle.