成唯識論述記 6.44

6.44

述曰：其可欣境，謂漏、無漏可欣之事方生於欲。此據情可欣，故通三性，非唯無漏實可欣法。於可欣事欲見、欲聞、欲覺、欲知，故有希望，即是四境之中所樂境也。

The Commentary states: A delightful sphere refers to delightful matters, both contaminated (sāsrava) and uncontaminated (anāsrava), toward which desire is only then generated. This is based on what is delightful to sentiment; therefore it pertains to all three moral natures, not only to truly delightful uncontaminated dharmas. Toward delightful things, one desires to see, desires to hear, desires to perceive, and desires to know; thus there is hope, which is the "desired sphere" among the four spheres.