idk...it makes sense to me, Then again i can see why it wouldn't as well. The emperor seems to be living in a place where factions exist and unrest between those who want a certain ruler, those who rule through religion and those who want power and the rights to claim it are at each others throats. By gaining a Queen this adds to unrest and anger as 1: he can now make and Claim an heir 2. They strengthen ties with another country, however superficial the ties may be. and 3. His status as emperor is a little more solidified.
by making her pretend to actually be just as evil as his rumors are about him, this makes them hesitate and with her seemingly in their eyes controlling the emperor, they can try and gain her favor so that she and he both do their(whatever factions')bidding. This brings the out the shadows and also gives the emperor an idea of how to get rid of them.

I'm not really following
He doesn't want people to think she is his weakness so he decided she should be a villainess and that He should act like he is whipped?
Doesn't it make look like he has a weak spot for her?
Anyway seems like it's going to be interesting with the priestess and all
Its going to be crazy and I can't wait