Each one makes first lady really disheartened (5)
I believe the answer is:
every
'each one' is the definition.
(I've seen this before)
'first lady really disheartened' is the wordplay.
'first' says to put letters next to each other.
'lady' becomes 'eve' (woman's name).
'disheartened' means to remove the middle letters (the middle or heart is removed).
'really' with its middle removed is 'ry'.
'eve'+'ry' is 'EVERY'.
'makes' is the link.
(Other definitions for every that I've seen before include "Each (one of a set)" , "The best possible" , "All, taken separately" , "Each single (item)" , "Each of a number" .)