Might be nicer in the southeast to be honest (7)
I believe the answer is:
sincere
'honest' is the definition.
(sincere can mean genuine or honest)
'might be nicer in the southeast' is the wordplay.
'might be' is an anagram indicator (I've seen this in other clues).
'in' is an insertion indicator.
'the southeast' becomes 'se' ('SE' can be a synonym of 'southeast').
'nicer' is an anagram of 'incer'.
'incer' put into 'se' is 'SINCERE'.
'to be' acts as a link.
(Other definitions for sincere that I've seen before include "'Genuine, not deceitful (7)'" , "Genuine and honest" , "natural?" , "Honest, heartfelt" , "Unfeigned, genuine" .)