Valmiki Ramayana Kishkindha Kanda Sarga 34 Shloka 15

मिथ्याप्रतिश्रवः who has made false promises, सः he, त्वम् you, ग्राम्येषु भोगेषु worldy pleasures, सक्तः engaged in, रामः Rama, त्वाम् you, मण्डूकराविणम् croaking like a frog, सर्पम् serpent, न विजानीते did not identify.

'You have failed to keep your word. You are engaged in worldly pleasures. Rama did not know that you are a serpent croaking like a frog.