One beloved Scotsman maybe about to come into money (7)
I believe the answer is:
fiancee
'one beloved' is the definition.
(a person's beloved)
'scotsman maybe about to come into money' is the wordplay.
'scotsman maybe' becomes 'ian' (Ian is a common Scottish name).
'about' becomes 'c' (abbreviation for 'circa').
'to come into' means one lot of letters goes inside another.
'money' becomes 'fee'.
'ian'+'c'='ianc'
'ianc' put into 'fee' is 'FIANCEE'.
(Other definitions for fiancee that I've seen before include "person waiting for match?" , "Woman engaged to be married" , "ringed girl" , "She's engaged to be married" , "Girl engaged to marry" .)