From the time of Rome, it took years to start with honesty (9)
I believe the answer is:
sincerity
'honesty' is the definition.
(sincerity is a kind of honesty)
'from the time of rome it took years to start' is the wordplay.
'from the time of' becomes 'since'.
'to start' suggests taking the first letters.
The initial letters of 'rome it took years' is 'rity'.
'since'+'rity'='SINCERITY'
'with' is the link.
(Other definitions for sincerity that I've seen before include "truth" , "Straightforwardness" , "Genuineness" , "Openness and truthfulness" .)