Pledge to raise expectations (7)
I believe the answer is:
promise
I believe this clue is a double definition.
'pledge' is the first definition.
(I've seen this before)
'raise expectations' is the second definition.
(thesaurus)
'to' is the link.
(Other definitions for promise that I've seen before include "Assurance" , "Betroth" , "Vow" , "plight?" , "Guarantee" .)