US readers relaxed and at ease (9)

I believe the answer is:
reassured
'at ease' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
'us readers relaxed' is the wordplay.
'relaxed' indicates anagramming the letters.
'us'+'readers'='usreaders'
'usreaders' is an anagram of 'REASSURED'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for reassured that I've seen before include "Freed from anxiety" , "Confirmed" , "Relieved of anxiety" , "confident" , "Comforted" .)
