Responses
Probably because she had no prior knowledge of the trade rules or politics which is why she had trouble answering it and as mentioned earlier, even a genius such as the crown prince had trouble in solving this matter so to simply put it was not a simple matter that anyone could solve.
So when did the blond empress candidate become quite smart and conniving? When she was first introduced she made a smart decision by getting Marie on her side, and taking credit for her ideas, but she literally could not make a single decision without her. If she was this smart from the beginning why not use those wits before?