For family class applications—spousal, conjugal partner and common-law relationships—the requirements under IRPA indicate assessment of a genuine relationship, and there are different qualifications for each of those three subcategories in family class.
For the most part, the assessment is done based on the evidence that is provided by clients and by the assessments done on paper. If there is insufficient information for the officer to be satisfied, then an interview may be required or additional documents requested. As part of the interview process, officers who undertake those interviews have undergone unconscious bias training. They're also seized with cultural issues and with being aware of the local context in which they are doing the interview.
For the most part, our first attempt is always to have evidence provided by the client that addresses the concerns that are being raised, and it's only in circumstances where that is insufficient that an interview is one of the options looked at for further assessment.