Reasons for Canadian visa officer's refusal to sign a visa

Visa officers must reject applicants according to Canada's immigration laws, not according to their own preferences. Then the immigration law only gives visa officers two reasons to refuse applicants. In other words, the applicant cannot convince the visa officer that:

Fund shortage

Have enough funds (legal after-tax income) to support study and life in Canada.

Will not stay in Canada

Will leave Canada after graduation.