Scratch that - it will cost absolutely nothing:
"We anticipate that debt charges will not go up, which is surprising and counterintuitive," Giroux said. "Interest rates are so much lower than what we anticipated them to be just two or three months ago. It doesn't cost that much to finance that growing debt.
"Is the government in a worrisome position right now? The answer is no."
https://www.cbc.ca/news/politics/federal-deficit-higher-than-252-billion-1.5566768
Don't be a crayon economist.
We will be very lucky if the combined federal and provincial debt to GDP is less than 100% by the end of the year.
If I were a foreign investor looking to buy Canadian debt, the first thing I would think of is the future of the currency. If they are only going to pay 1% interest and I flgure the Canadian dollar will devalue by 5%, I will be 4% better off putting my money under my mattress.
What will more likely happen is the BoC will lend the money to the government and then buy back the debt, in other words print money. That is what the US has been doing since 2009. Problem is, we aren't the worlds reserve currency.
Were you even alive in 1993 and if so, why weren't you paying attention.