chivalry fell on its sword

Joanna is the only daughter of the king, and has yet to choose a husband. The solution? Typical princess-in-a-tower thing- whoever saves her is the most worthy.
But she just isn't ready for that- or so she says. She turns down countless suitors before they can even climb to the top, and people are beginning to suspect she's a little too close with her lady-in-waiting.
basically!! a fantasy-type story about a princess in a tower, also lesbians