It may develop into friendship (5)
I believe the answer is:
amity
'friendship' is the definition.
(I've seen this before)
'it may develop' is the wordplay.
'develop' indicates anagramming the letters.
'it'+'may'='itmay'
'itmay' is an anagram of 'AMITY'.
'into' is the link.
(Other definitions for amity that I've seen before include "Cordiality" , "Friendship - goodwill" , "warmth" , "understanding" , "Friendliness" .)