Romeo x Juliet, Ribbon no Kishi Recommendations
Romeo X Juliet isn't as close as the original masterpiece of Shakespeare than it is from Princess Knight. After all, Juliet family was wiped out, and she decides to act as a boy for some time, to be the scarlet justice defender like Sapphire acts against the evil ministers of her kingdom. Apart from that the story is different, there is romance in Princess Knight as there are in Romeo X Juliet (and the first ten episode of the series reminded me of Ribbon no Kishi).
Ribbon no Kishi is an Osamu Tezuka masterpiece, it's part of the very story of the japanese animation, watch it.