“It’s always calmest before the storm.”
This phrase is known and used for those situations when the good times must surely predate (or even predict) an encroaching ugliness. It’s succinct in usage, and it’s easy to understand. But it’s also rather pessimistic. A doom-and-gloom approach to what life brings on the horizon.
Because that which follows a storm can have a balanced sense of optimism. The warmth of sunshine. The colorful image of a rainbow. The smell of fresh nature. So, those ugly times may arrive without remorse, but goodness can prevail. If nothing else, Koi wa Ameagari no You ni adheres to this stance, promising a phenomenal anime containing a similar happiness.