gpt
Subaru Natsuki:  Subaru’s theory was that ease of falling asleep and ease of waking up were inversely related. To him, waking up felt like being underwater and having his head break through the surface. No one would ever forget to breathe once their head was above water. So waking up was just natural to him and not something that felt difficult to do.
human
Emilia:  "I’m jealous you can wake up so easily like that. It’s always reeeally hard for me." Emilia's response when they had talked about it once before.
gpt
Subaru Natsuki:  That trouble was deeply ingrained for Emilia, and she had pretty intense bouts of low blood pressure. It sort of fit her character, but it usually took an hour or so to actually get out of bed after waking up. But the ease with which she could fall asleep was like a child, the polar opposite of Subaru. No matter how hard he tried, when he lay down and closed his eyes, he would end up thinking about things in the dark. A large number of them were various regrets, “If I had only…” and “If it was just…” and the like. The regrets were about things that had happened that day and things in the past. Whatever his mind happened to drift to. And while he was fighting all those thoughts, Subaru couldn’t manage to fall asleep. That was the root of his trouble sleeping.