Two things happen, both designed to make rejection less stinging.
First, your 5 Sparks are refunded, if the rejection happens within 7 days of the request. The 5 Sparks weren't a punishment; they were a small filter. If the answer is no, the cost goes back to you.
Second, the rejection itself is silent on your side. You don't get a notification that says "[Name] rejected you." The request just quietly disappears from your sent-requests list. The other person's profile may become harder to find again (depending on their privacy settings). That's the only signal. We do this on purpose: public rejection notifications would turn the whole system into something painful, and we don't want Cofelt to feel like that.
The most important thing to remember: a no in this moment is not a permanent answer. Timing and circumstances change.