The Lonely Snow Widow and the Cursed Ring

In a modern world where various races coexist,
Takahashi Satoru, who inherited his late father's management of "Yoyogi Heights," an apartment building exclusively for yokai (supernatural beings), finds himself drawn to one of the residents, Yukino Mifuyu, a widowed snow woman.
One day, Satoru angers her with careless words, and discovers a mysterious ring that seems to be his father's heirloom.
It appears to have the power to facilitate communication with yokai, and he eagerly tries to use it to reconcile with her...

Specifically, it's a ring that "amplifies the emotions that a yokai has towards the wearer."
Using its power, Satoru and Mifuyu made passionate love, but the next day he discovers that when he uses the ring, Mifuyu has no memory of it.
Still, Satoru doesn't give up, believing that she doesn't hate him, and helps her rebuild her life.
When he hears Mifuyu's story about how she's having trouble finding work, he realizes that while she has her own struggles as a snow woman,
she also seems to have some significant problems with her communication skills...

Satoru became friends with Mifuyu to help her get used to people.
They exchanged contact information, but as expected, they didn't communicate much.
Then Mifuyu came to the manager's office. She
said there was a package she didn't remember receiving, so Satoru went with her to her apartment, room 503, to check it out.
Upon investigation, it turned out to be a misdelivery. The online store that sent it asked Satoru to dispose of it, and he casually invited Mifuyu to eat it together if it was food, but...