Manage to be straightforward (6)
I believe the answer is:
direct
I believe this clue is a double definition.
'manage' is the first definition.
(I know that direct is a type of manage)
'be straightforward' is the second definition.
(straightforward can mean direct)
'to' acts as a link.
(Other definitions for direct that I've seen before include "Point the way" , "Instruct" , "Candid" , "Frank; unambiguous" , "Creepy-crawly" .)