CMHC, Sagen and Canada Guaranty insure most Canadian mortgages with less than 20 percent down, but none of them set your rate, that is between you and your lender. What they do not change is the compounding: virtually every Canadian mortgage, insured or not, compounds semi-annually even when quoted as a fixed annual rate.
If your closing is more than 120 days out, ask your lender about a longer rate hold, since not every lender offers the same length. Missing the hold window means re-qualifying at whatever rate is posted on the day you actually close, which can change your payment.
Joel Dyck times the listing and closing schedule with your mortgage rate hold in mind, so financing does not become the reason a good deal falls apart. Get your hand-reviewed valuation from Joel Dyck.