Said to be satisfactorily enclosed in new pens (6)
I believe the answer is:
spoken
'said' is the definition.
(I've seen this before)
'satisfactorily enclosed in new pens' is the wordplay.
'satisfactorily' becomes 'O.K.' (synonyms).
'enclosed in' is an insertion indicator.
'new' indicates anagramming the letters.
'pens' is an anagram of 'spen'.
'ok' inserted inside 'spen' is 'SPOKEN'.
'to be' is the link.
(Other definitions for spoken that I've seen before include "released from trap" , "Oral" , "Verbalised" , "Declared" , "Verbal" .)