Green’s Dictionary of Slang

(US Und.) a confession.

1907		Eve. Statesman (Walla Walla, WA) 21 Dec. 1/7: I dona wanata die [...] You understand? Make no confesh. See?
1912		A. Berkman Prison Memoirs of an Anarchist (1926) 192: The muttonhead sent for th’ district attorney the same day, an’ signed a third confesh.