How do I tell someone they didn't get the promotion?

Right now your silence is doing the talking, and it is saying something crueler than the truth would. They can feel that something happened. Not knowing why is worse than any answer you could give. Avoiding the conversation does not protect them. It only leaves them alone with their guessing. They earned a straight answer from you. Not a soft blur, not a delay, but honesty about why the decision went the way it did and what would change it. That respects them as an adult who can handle the truth. It also respects you, because carrying an unsaid thing costs you more than saying it ever will. Set the conversation this week. Keep it simple: tell them the outcome, tell them the honest reason, and tell them one real thing they can work on. You do not need the perfect words. You need to show up and stop letting the silence speak for you.