Reborn as the Princess Known as a Burden, I Fell in Love With the Hero and Became the Saint

A sickly girl is reincarnated in another world as a princess. However, she is looked down on as she does not possess any type of magic. Her purification ability awakens just in time a hero is summoned from another world. Feeling needed for the first time, she starts to fall in love with him... but, for some reason his attitude seems cold?