ah, you shouldn't be worried.
they are checking if your fiance is really going for the business, or she/he has bought this visa. simple. If they found it's illegal visa your fiance will be jailed, and then they will trace to qatar and find who issued a visa for her (him), and this person will be jailed too...
don't worry...

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"What lies behind us and what lies before us are small compared to what lies within us."
Oliver Wendell Holmes