Valmiki Ramayana Ayodhya Kanda Sarga 34 Shloka 57

अनघ O sinless, पार्थिव O king, मे मनः my mind, शिष्टसम्मते acceptable to the disciplined (wise), तव निदेशे by your order, यथा as, धीयते is contained, तथा in that way, महत्सु great, कामेषु pleasures, न not, आत्मनः mine, प्रिये dear, न not, मत्कृते on my account, तव your, दुःखम् grief, व्यपैतु shall be expelled.

O king my mind derives no happiness from great enjoyment or personal comfort as it does from carrying out your order. This is corroborated by the wise. Your grief (relating to filfilment of the vow) on mt account will be dispelled, O sinless one