Well this is more of a comedy but it has some romance in it
It´s called Seigi no Mikata ...
Description:
15-year-old Yoko, a young girl who is constantly tormented by her self-centered and devilish older sister Makiko, who works for a government office after having graduated from a famous university. But despite her ill nature, Makiko's actions tend to somehow make things better for those around her, causing others to praise her as an "ally of justice."
I watched it at mysoju.com ;Z