Maybe Rosie takes us to be important (7)
I believe the answer is:
serious
'important' is the definition.
(similar in meaning)
'maybe rosie takes us' is the wordplay.
'maybe' indicates an anagram.
'takes' is a charade indicator (letters next to each other).
'rosie' with letters rearranged gives 'serio'.
'serio'+'us'='SERIOUS'
'to be' acts as a link.
(Other definitions for serious that I've seen before include "Earnest - important" , "Important -- grave" , "Stern" , "Not light or frivolous" , "Earnest, sincere" .)