Girl strangely hard about love (5)
I believe the answer is:
rhoda
'girl' is the definition.
'strangely hard about love' is the wordplay.
'strangely' indicates anagramming the letters.
'about' means one lot of letters goes inside another.
'love' becomes 'o' (love means zero in tennis).
'hard' anagrammed gives 'rhda'.
'rhda' enclosing 'o' is 'RHODA'.
(Other definitions for rhoda that I've seen before include "Woman" , "Girl" , "Fem. name; hoard (anag.)" , "Girl's name; hoard (anag.)" .)