Roselia Oukoku Monogatari: Himegimi to Utsukushiki Kyuukonshatachi

Roselia's husband is to be chosen at a ball, and suitors from all over the world, princes, have gathered!
But Roselia's love interest is a former assassin. Will this love be fulfilled...?

(Source: Oozorashuuppan, translated)

Note: Also includes Wagamama Hime no Hatsukoi (わがまま姫の初恋).