A leader who cannot admit uncertainty teaches everyone beneath them to hide theirs.

A leader who is never uncertain teaches everyone that uncertainty is unacceptable, so it goes underground. People then present false confidence upward, and decisions get made on information that has been smoothed for presentation. The cost arrives later and is much larger than the admission would have been.

Say plainly when you do not know something, and say what you are doing about it. That one habit changes what gets reported to you, which changes the quality of everything you decide.