It is indeed a nuance. The French term “assurer”, or “ensure” in English, implies that the Government of Canada would have an obligation to ensure certain results in an area of shared jurisdiction.
The provinces play a fundamental role here, never mind the fact that the success of francophone immigration depends on a multitude of factors. These include attracting and retaining immigrants, as well as the labour market, which remains fundamental. Of course, delivering essential services, including health care and education, in the communities or different regions also means that the provinces, territories and municipalities have an essential role to play.