Was ich im Herzen hab, das sag ich mit dem Munde.
Wer mein gesicht betracht, schaudt meines Herzens grunde.

What I have in my heart, that say I with my mouth.
Who looks upon my face, sees the bottom of my heart.

From a book published in 1694 called'The Revised Compendium and Engraving Booklet [with] hundreds of spiritual and secular heart seals/mirrors for a particular illustration of the Virtues and Vices presented and explained with hundreds of poetic conceits by Fabian Athyrus, devout in the praiseworthy Intellectual Arts'.
Discovered via Bibliodyssy- one of my favourite blogs.