Assistant turning fruit crop up (6)
I believe the answer is:
appear
'crop up' is the definition.
(I've seen this in another clue)
'assistant turning fruit' is the wordplay.
'assistant' becomes 'PA' (personal assistant).
'turning' says the letters should be written backwards.
'fruit' becomes 'pear' (pear is a kind of fruit).
'pa' in reverse letter order is 'ap'.
'ap'+'pear'='APPEAR'
(Other definitions for appear that I've seen before include "Become visible like ghost" , "Materialise like ghost" , "Seem - emerge" , "Come into sight, materialise" , "Become visible or seem" .)