Even worse than the chances of getting a visitor visa when you are not also applying for a PR visa: in other words, for an applicant from West Africa, extremely low.
If you can provide everything the visa office asks for in terms of proof that you will leave Canada before the TRV expires, the chances are still low. You need proof of a job - businessmen and traders I know have all been refused, with one of the reasons being their lack of a job; proof of owing a house; more family ties back home than in Canada - so children left behind are good, but better evidence for a woman than a man; money in the bank and investments; proof of enrollment in an educational institute that starts after your return date, and payment for this, is also useful.
How many West Africans with a spouse in Canada can provide all this?