Disturb the girl's hair
I believe the answer is:
distress
'disturb' is the definition.
(distressing is a kind of disturbing)
'the girl's hair' is the wordplay.
'the girl's' becomes 'dis' (Di is short for Diana).
'hair' becomes 'tress' (tress is a kind of hair).
'dis'+'tress'='DISTRESS'
(Other definitions for distress that I've seen before include "grief" , "Cause mental pain" , "Deep anxiety" , "State of anxiety or woe" , "State of suffering" .)