Rejection emails fail in two directions. Written quickly they read as cold, and the reader spends a day deciding whether they did something wrong. Written carefully they fill up with softening — "we were so impressed", "please do stay in touch" — until the actual decision is buried and the reader comes away thinking a door is still open when it is not.
This prompt separates the two jobs. It rewrites the message so the decision lands early and the reason given is true, and then it reports back on the sentences in your draft that promise something you did not mean. That second half is the useful part: false hope is almost always accidental, and it is very hard to spot in your own writing.