when I looked at the cover of this book, I imagined that this story was so relaxing.
However, once I read this a few pages, I knew this book didn't match me. 聼起來自然嗎?

@sushi-pikachu-totoro: ok, so it's mostly natural. however, I would rephrase "I imagine that this story was so relaxing"...perhaps to something like, "I imagined the story would be more interesting," or "I thought the story would be a little more relaxing"...something like that...