Valmiki Ramayana Sundara Kanda Sarga 11 Shloka 39
Original Shlokaतस्य प्रादुरभूच्चिन्ता पुनरन्या मनस्विनः।।5.11.39।। निश्चितैकान्तचित्तस्य कार्यनिश्चयदर्शिनी।
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मनस्विनः highly sensible, निश्चितैकान्तचित्तस्य struck with a bright idea in a single direction, तस्य his, पुनः again, कार्यनिश्चयदर्शिनी the decision regarding the task ahead, अन्या other, चिन्ता thought, प्रादुरभूत् arose.
Another bright idea struck the highly sensible Hanuman, who had a clear vision of the task ahead-- 'I was firm and singleminded in my direction regarding the task ahead' (thought he).