Dragon Knight

Dragon Knight (ドラゴン　ナイト) is a manga series by Miyuki Yamaguchi. It was serialized in Hana to Yume.

Plot
Gurian, a dragon knight, in search of a girl who has the special ability to use the power of the stars to stimulate fertility in the country's lands, comes upon Rin. Rin is just a country girl who has a sick grandfather and young brother to take care of. Seemingly, she's a simple farmer whose main characteristic is that she talks a lot. Could she really be the next "princess of the stars"? And what happened to the previous princess that prompted Gurian to go on this journey to begin with?