If I'd known you were coming, I'd have shaved my beard

Da "parody on da cake-baking saying" remark dat you smilingly say to a cute chick whom you've unexpectedly met somewhere, and you are savoringly pressing her soft warm palms against yer fuzzy cheeks.

I always love joking around about, "If I'd known you were coming, I'd have shaved my beard" wif pretty girls whom I befriend; said humorous remark always gets da biggest amused giggle-fits outta dem.

to be known to the Unforegivables

(Unforegiveables always with a capital u): to have a criminal record, most likely in the United States

To be known to the Unforegivables,, as a phrase, comes from the fact that if you have a criminal record in the United States it almost certainly is for life.