This is a phrase that you say to someone, before you tell them about something negative. For example, a manager can tell an employee that another employee was fired:
Hey, listen. I have some bad news. We had to let Bradley go today.
The phrase "I have some bad news" is appropriate for serious problems like:
- someone losing their job
- getting in an accident
- not getting selected for a job, a school, an award, etc.
- losing money
- the death of someone you don't know well
But it's not strong enough for really bad events, like the death of a close friend or family member. In that situation, phrases like these are better:
Lana, I have some horrible news. Aunt Coco was killed in a car accident.
A: What's wrong?
B: Something terrible has happened. Jana was shot.