Ramayana
सर्वथा सुकरं मित्रं दुष्करं परिपालनम् । अनित्यत्वाच्छ चित्तानां प्रीतिरल्पेपि भिद्यते ॥ ४-३२-७
'It is easy to earn a friend but keeping the friendship sustained is difficult. Due to fickleness of mind friendship gets broken even on flimsy grounds. ॥ 4-32-7॥
english translation
sarvathA sukaraM mitraM duSkaraM paripAlanam । anityatvAccha cittAnAM prItiralpepi bhidyate ॥ 4-32-7
hk transliteration by Sanscript