I think this lady is hoping to get close to a capture target? Or perhaps a newly formed yandere? It kind of seemed like she was being controlled or something at the dinner. Black magic maybe?
Eh. I'm enjoying it. They've definitely Flanderized Katarina and made her even more of an airhead (if such a thing is possible), but I don't think that's always a bad thing. Also, the concept of people expecting her to react like a normal person to things only for her to be absurdly optimistic will never stop being funny to me.
Is her reason going to be something as dumb as her loving the prince and wanting them to break their engagement so she can have her chance... ? Please let it not be so, that would be such a cliche.
I'm a firm believer that is from this point that this series goes really bad, reusing the same plot again and again, and Katarina especially goes from being innocent and dense to fully retarded. You don't believe me? Wait around two to three chapters more and you will see.