The amount of information that people are inclined to share with you privately rises in direct proportion to how well you handle the information others have given you.
To put it in a much simpler way, if you lead any sentences with “I shouldn’t tell you this, but …” then you’re doing the wrong thing.
Don’t ask others to keep things secret for you. Know who you can trust, who has discretion, and make being careful the default mode.
Some people like to spill the beans of the juicy gossip. Others, the smart ones, don’t like cleaning up the mess so they never do the spilling. Keep private conversations private, watch your ‘trust stock’ go up, and never forget that your reputation is one of the most valuable assets you own. Treat it carefully, for it is fragile.