Conflict from desperate sweetheart about sink (8)
I believe the answer is:
disagree
'conflict' is the definition.
(I've seen this before)
'desperate sweetheart about sink' is the wordplay.
'desperate' becomes 'dire' (I've seen this before).
'sweetheart' becomes 'e' (the middle letter or heart of 'sweet').
'about' indicates putting letters inside.
'sink' becomes 'sag' (sagging is a kind of sinking).
'dire'+'e'='diree'
'diree' going around 'sag' is 'DISAGREE'.
'from' is the link.
(Other definitions for disagree that I've seen before include "Differ in opinion" , "Contradict" , "Differ, argue" , "Quarrel" , "Hold a differing opinion" .)