好事不出门坏事传千里

好事不出门，坏事传千里:

Literally means:

good news never goes beyond the gate, while bad news spreads far and wide; honor goes to crutches while discredits fly aspace.

Actually means:

It means that good news is hard to spread while news of bad deeds spreads quickly.

Bad deeds refer to immoral or illegal acts and un pleas sant or dissatisfactory things. (The latter are usually the things that one doesn't want others to know).

好事不容易被人知道，坏事却容易传播开来。“坏事”指违反道德或法律的事，以及不开心或不如意的事(后者通常是不希望让别人知道的)。