Valmiki Ramayana Kishkindha Kanda Sarga 8 Shloka 10
Original Shlokaतत्तथेत्यब्रवीद्रामस्सुग्रीवं प्रियवादिनम्। लक्ष्मणस्याग्रतो लक्ष्म्या वासवस्येव धीमतः4.8.10।।
1 source checked for this shloka
रामः Rama, वासवस्य इव like Indra, धीमतः wise, लक्ष्म्या by signs, लक्ष्मणस्य Lakshmana's, अग्रतः in the presence of, प्रियवादिनम् pleasant speaker, सुग्रीवम् Sugriva, तत् that, तथा it is true, इति thus, अब्रवीत् he spoke.
As wise Lakshmana, brilliant like Indra stood witness, Rama said, 'it is true as you say' to Sugriva who spoke pleasing words.