Jiang Yuebai did not tell the female ghost that she had the Merfolk Pearl which could restore the Divine Soul. She decided to wait and see.
There are no Merfolk in the Azure Dragon Realm, and Jiang Yuebai was unsure if other realms had Merfolk. If not, the rarity of the Merfolk Pearl would far exceed the Yellow Springs Flower and the Three Paths River Water.
The reason the Yellow Springs Flower and Three Paths River Water are rare is that they are located on the road to the Netherworld.
In the Earth Spiritual Realm, Merfolk are envoys of the Netherworld, and to go there one must pass through the Merfolk Country. Hence, few Ghost Cultivators can go to the Netherworld through the Merfolk Country and then return.
For this reason, the Earth Spiritual Realm does not have Yellow Springs Flowers or Three Paths River Water.
