von Mann zu Mann

German

Literally, “from man to man”. Compare also man-to-man.

(idiomatic) in private and in total honesty (of two men; sometimes used to indicate that the person is familiar with the matter at hand, especially if concerning male topics)
Synonym: (close) unter vier Augen

Von Mann zu Mann, es wird nicht besser.
To be completely honest, it won't get any better.
Used other than figuratively or idiomatically: see von,‎ Mann,‎ zu.