Oh My Goddess! Vol 30

From the Dark Horse edition

As powerful (and wrathful) as Belldandy's older sister Urd is, what's the real reason she never became a Goddess First Class? Now, in order to finally achieve that exalted state, Urd must fulfill a challenge decreed by Peorth: give Keiichi a certain amount of happiness! That sounds great... until you realize that with Urd, giving a certain amount of happiness is going to mean inflicting a great amount of misery first!

Source: Anime News Network Encyclopedia