Hi Harkiran,
Processing time varies from case to case.... and it also depends on the quality of the documentation/evidence submitted as well as the applicant's situation/purpose of visit.
It is possible for someone's TRV application to be processed in even a couple of days/a week.... like it has happened in the case of IndoCanadian2015.
A delay may be possible if additional checks/additional information is sought by the visa office from other sources.
Hope your fiance gets his TRV soon
Cheers