She may not know Daryl but Clara was a pretty good reader of people, so she could pick up on the sincerity. Which was nice, even if she did technically cheat in the way the food was made because of the TARDIS. She knew she got chided for using the TARDIS in emergencies in the Dreams, but her own TARDIS didn't seem to mind the ruse.
"I am, too. I hope to see you around."
Even if it would be in a different location because the diner did like to change locations depending on the day.