Twice a day, gets through to her (3)
I believe the answer is:
ada
'to her' is the definition.
'twice a day gets' is the wordplay.
'twice' indicates the doubling of some letters.
'day' becomes 'd' (abbreviation for day).
'gets' means one lot of letters goes inside another.
'a' doubled is 'aa'.
'aa' enclosing 'd' is 'ADA'.
'through' acts as a link.
(Other definitions for ada that I've seen before include "-- Lovelace, pioneer in computing" , "Girl's name, one letter short of a man's name" , "girl?" , "Computer language; girl's name" , "Woman" .)