Old man with sweetheart in spot — reportedly a very low point (4,3)
I believe the answer is:
dead sea
'a very low point' is the definition.
(lowest point on Earth)
'old man with sweetheart in spot reportedly' is the wordplay.
'old man' becomes 'da' (da can mean dad).
'with' is an insertion indicator.
'sweetheart' becomes 'e' (the heart/centre of 'sweet').
'in spot' becomes 'ads' (I am not sure about this - if you are sure you should believe this answer much more).
'reportedly' becomes 'e' (I've seen this in other clues).
'e'+'ads'+'e'='eadse'
'da' placed around 'eadse' is 'DEAD SEA'.
(Other definitions for dead sea that I've seen before include "large salt lake" , "R. Jordan lake" , "Didn't win; TV series" , "At 400 m below seal level, the world's lowest point" , "Salt lake fed by the Jordan river" .)