>>48477867She isn't
>>48477876 is correct.
That being said, Diantha definitely is the most graceful. There's a stupid amount of dignity and she has a pure beauty that I don't think any other Pokegirl has.
As far as sexiness goes, I'd probably give that to Cynthia, Lusamine or Melony. The latter because despite her fat she knows how to use all that cushion and how to give you them bedroom eyes.