I think there are different situations in which you can have a marriage of convenience. One of them may be that there is some sort of consideration, a monetary consideration or other that, for instance, the sponsor receives for engaging in a marriage of convenience. It may also be that the sponsor is unwitting and is the victim of a marriage of convenience from someone who pretends to wish to marry them and of course has no intention of staying with them.
On February 26th, 2014. See this statement in context.