ꜱᴇᴄʀᴇᴛ. ~ ᴋᴀɴᴀɴᴇᴢᴜ

In this, Shinobu is kinda like Sanemi. She hates demons meaning that Nezuko wasn't accepted in her eyes. Shinobu just doesn't trust Nezuko at all.

On the other hand.. Kanao soon falls in love with Nezuko.. Kanao keeps her relationship with Nezuko a secret.
...but with Shinobu being around so much, along with hating Nezuko, it becomes hard for Kanao to keep her secret relationship with Nezuko.