You can never truly know these days. First, some people know how to communicate to their advantage and play the right fiddle. Second, these things can change quickly, for professional or personal reasons.
My gut feeling tells me Jeff Petry is at the right spot in his career to be happy playing here, and seems so.
In recent history, PK Subban clearly had Montreal tattooed on his heart, and the fact that he still seems to have tells me it was truly heartfelt.
Historically, anyone playing for the team in the 60s/70s was probably REALLY happy to keep winning and winning while the city was economically and culturally booming.