I need a word/phrase to describe something that is part of a routine and guaranteed to happen. It's kind of hard to explain but hopefully, the example will help clear things up :)
I'm writing a story, which is from the perspective of a pet cat, and in this particular section, the owner is leaving to collect groceries and the cat is at home, waiting for the owner to return and with cat food.
"The isolation and sorrow I experienced every week for these lonely thirty minutes was only made bearable by the [word/phrase]"
Originally I had "only made bearable by the promise of cat food" but I felt like it wasn't quite right. Any suggestions will be appreciated.