Three words: damsel in distress.
If you like a weak female protagonist who always gets kidnapped and can't save herself, this is the one for you. I usually don't, unless it's realistic. The main character is a princess. She's very sheltered. Therefore, she's gonna be kinda helpless. There wasn't much character development, but the characters are understandable nonetheless.
One more thing. If you are looking for a pirate manga, this isn't the one for you. There isn't any pirate action whatsoever. I love pirates. That's the thing that turned me off.
Still, I enjoyed this manga. You should give it a shot.