Grand woman hosting leader of Lords with pleasure (6)
I believe the answer is:
gladly
'with pleasure' is the definition.
(I've seen this before)
'grand woman hosting leader of lords' is the wordplay.
'grand' becomes 'g' (G is short for grand as in a thousand).
'woman' becomes 'lady' (lady is a kind of woman).
'hosting' means one lot of letters goes inside another (inserted letters are welcomed in or hosted).
'leader of' indicates taking the first letters.
The initial letter of 'lords' is 'l'.
'lady' enclosing 'l' is 'ladly'.
'g'+'ladly'='GLADLY'
(Other definitions for gladly that I've seen before include "Delightedly" , "With pleasure" .)