This doesn't fit our use case.

"Can you tell me more about your use case? I've had this conversation before and sometimes the gap is smaller than it looks."

"What's your core use case? I want to show you how we've handled exactly that for companies like yours."

"I appreciate you being direct. If there's a genuine gap, I'd rather know now than oversell you on something that won't work. Can you walk me through what's missing?"