It will say that they doubt that she is a genuine visitor and that she will return to her home country.
@niki4chris - your extension was rejected because you have already had two extensions. IRCC no longer believes you are a genuine visitor - and I think you know that you are no longer a visitor, either. You should have applied for spousal sponsorship a year ago - staying a visitor for 1.5 years makes it clear you're not visiting but you
also haven't done anything to advance your status.
What can you do now? First, pay the PR fees. All of it. Then apply for restoration of your status, with "applying for PR" as the reason for your restoration application. Attach the receipt of the PR fees as proof of intention to apply for PR. Then apply as soon as you possibly can. Within the next month or so.
Long story short: 1.5 years of a stay
without applying for PR means you are no longer a genuine visitor and will be denied a visitor extension. If you plan to apply for PR, do it within your first six months' admission, or if you need to establish common-law, after the 12-month mark.