What about singing out of tune?

Some people are not sensitive to timbre and don't understand vocal music, so it is good for such people to practice more.

Others are suffering from diseases. Being born with tone-deaf is no joke. In that case, I can only run away in my life.

The way to judge is: it is not bad to run every capital or several capitals. People with aphonia can't sing all scales correctly.

Just practice more and listen to it a few times before singing.