Cant remember the name of this manhwa I read years ago and I only vaguely remember the plo...

Cant remember the name of this manhwa I read years ago and I only vaguely remember the plot. It’s a shoujo historical where the main character is a commoner girl (brunette) who somehow becomes the maid of a noble girl (black hair) that was passing by. The noble girl abd the commoner girl had a short of frenemy relationship. The noble girl was on her way to a marriage competition(?) where multiple noble ladies were chosen to stay at this big mansion for a while and undergo a series of tests to see who was best fit to mark the Prince.

The plot twist was that the black haired noble lady was actually the prince disguised using magic, he disguised himself as a lady in the competition to keep a close eye on all the noble lady candidates to see their real personalities/attitudes when they weren’t around him as the prince.