Rob_TO said:
You do realize this is tax fraud and if CRA learns of it, you will be audited and face stiff fines/penalties for not reporting your income. If you are telling CIC about the income, not to mention making regular deposits into your bank account, don't be surprised if at some point CRA learns of it as well.
I was thinking the same thing.
The sponsorship document checklist requires that you submit a your Notice of Assessment for the most recent year (Part 16) and proof of employment (Part 17).
http://www.cic.gc.ca/english/pdf/kits/forms/IMM5491E.pdf
Unfortunately, the two aren't going to match. So you've got a problem. You'll have to either knowingly under-report your income on your sponsorship application, or accurately report your income on your application and try to explain to CIC why your Notice of Assessment doesn't match it. In the first case, your application may (will?) be denied if CIC learns you were intentionally untruthful in your application. In the second case -- well, I'm not sure how you would pull that off.
The best thing to do is come clean with CRA. Re-file your income taxes, and report the full amount of income your earned in 2015. From what I understand, CRA does not punish people who voluntarily re-file their income tax return with corrections. Of course you'll owe them tax, but I can think of worse things (see above). If you are able to re-file electronically, you should have a new Notice of Assessment available fairly for 2015 available fairly soon. Include this, along with a letter from your employer, in your sponsorship application.
I know this sounds awkward but I think it's much better than the alternatives.