Tomodachi no Hanashi友だちの話 ; 朋友的故事 ; 朋友的话语 ; The Secret of Friendship

From etc: Eiko is something of a plain Jane and a doormat, while her best friend Moe is a head-turning beauty. Despite their differences, their friendship is as strong as ever. Guys are always asking Moe out, but her answer is invariably "Only if you promise to put Eiko before me.”