Sense it should be "toi et moi" (4)
I believe the answer is:
nous
This clue is a double definition.
'sense' is the first definition.
(I know that nous is a type of sense)
'toi et moi' is the second definition.
(I've seen this in another clue)
'it should be' is the link.
(Other definitions for nous that I've seen before include "Common-sense" , "Abroad we" , "Common sense: mind or reason" , "Common sense - intellect" , "Savvy" .)