Hakushaku to Yousei Shinshi no Itomekata Oshiemasu

In this series of short stories—set before Lydia officially accepts Edgar’s proposal—Lydia first finds herself confronted by her self-proclaimed future child, who announces that she must marry Edgar or he will not be born. But could he really be theirs? Next, a mysterious nightingale fairy educates Lydia in the ways of love. And finally, this volume also includes the romantic and mystical tale of the marriage of Lydia’s parents, whose secrets are to be revealed at last! (Source: J-Novel Club)