She gives Rosalie heart (3)
I believe the answer is:
sal
'she' is the definition.
'rosalie heart' is the wordplay.
'heart' indicates the central letters.
The middle of 'rosalie' is 'SAL'.
'gives' is the link.
(Other definitions for sal that I've seen before include "girl?" , "Sarah (dim.)" , "- - volatile" .)