"Oh-um-actually...I-I was writing a note back..."
Dear Mysterious Stranger,
It's nice that you wanted to talk to me, but this whole letter thing is a little bit sketchy-also you know if you tell someone not to snoop around it's only going to make them more curious, right? Actually, that's why I wrote this letter in the first place-out of curiousity. If you really want to talk, then come meet me at my shop and stop being a stranger. I'd be happy to talk there-seriously, I don't bite. Oh, and thank you for the rose-it was a very nice gesture.
P.S.-if this is the count, please don't be too nervous to come to my shop!