Lady accepting resistance to tie the knot (5)
I believe the answer is:
marry
'tie the knot' is the definition.
(I've seen this before)
'lady accepting resistance' is the wordplay.
'lady' becomes 'mary' (**).
'accepting' means one lot of letters goes inside another.
'resistance' becomes 'r' (abbreviation).
'mary' placed around 'r' is 'MARRY'.
'to' acts as a link.
(Other definitions for marry that I've seen before include "Join - get wed" , "Get hitched" , "Gain a wife or husband" , "expression of surprise once" , "Well I never!" .)