This is purely a guess, but it seems:
First of all setting: she’s at the mansion of the least greedy inviters, whose invitation she accepted.
The sequence of events:
The stalker that followed her even when she closed the door, wanted to exploit her and use any cracks in her defence/ any weaknesses she might have, or at least planned to. As she will be Queen(or is it empress?) soon. When she said “don’t wanna” he got agitated, felt insulted, so inturn insulted her(really stupid). When the Prince appeared. Given his wicked character for blaming others for no reason/ for fun, it seemed his “cup of tea” to “punish this stalker”. He probably appeared that time for a chance to talk to FMC(or attack her, idk) but stayed for the wicked punishment game.