Starts to feel insecure and nervously calls editor... he's engaged (6)
I believe the answer is:
fiance
'he's engaged' is the definition.
(I've seen this before)
'starts to feel insecure and nervously calls editor' is the wordplay.
'starts to' says to take the initial letters.
The first letters of 'feel insecure and nervously calls editor' is 'FIANCE'.
(Other definitions for fiance that I've seen before include "He's going to marry" , "Engaged male" , "who may be planning marriage" , "The man she's engaged to" , "One's betrothed" .)