One of the greatest skills you can learn as a leader is how to be clear and direct in your communication.
Being "nice" and tiptoeing around the truth to avoid hurting someone's feelings isn't effective.
If anything...
It's dishonest and will keep these people from hearing the hard truths they need to hear to get better.
Your job as a leader is not to make people feel good.
Your job as a leader is to hold your team to the highest standard possible in order to win.
...and when someone on the team starts cutting corners and fucking up...
You have to reinforce the standard and hold them accountable.
Speak the truth.
Say it clearly.
Say it directly.
Not everyone is going to like it...
Most won't.
But even if there are people on your team who hate you for it now...
They'll learn to love you in time because you told them the truth and helped them get better when nobody else did.
That's true leadership.