I saw the trailer of this anime on the Bleach DVD Volume 1, which was featured in the Extras > Trailers. Other anime trailers that were featured on the DVD were for Black Cat, One Piece, Death Note, Eureka 7, Dragon Ball Z remastered and that's all I remember.
For the unknown anime trailer:
The song sounded like j-techno with female singer. I could recalled an English part of the lyrics being "I need you, I just kiss you, in my life"
Opening sequence shows a nude (?) girl in her early/mid teens with long pale blue hair tiptoed on the water
The main character (?) is a boy in his early/mid teens with gold brown hair that is shaped like razors on the sides and wears red clothing
(Image of hair colour, maybe 1 or 2 shades darker)The girl wears a black dress and has a black/white ribbon wrapped around her hair, kind of like a double helix.
(Almost identical to the image of the girl in the trailer)The main character and the girl seem to be romantically linked, as they are seen holding hands and the girl comforts the boy.
Other characters in the trailer are shown one by one with small girl figures popping up behind them. Maybe the little girls are spirits or guardians?
That's all I have for the description, I've tried so long to find out what this anime is and I couldn't find anything related to it except for the picture of the girl.