I'm a beginner at chess, can anybody explain me this probleme

Trier:
gipsy_jetsept

Hello, i have been spending twenty minute for finally making a mistake. In what the Knight will be dangerous in F6 for the King ? It seems black will have many option ? Thanks.

Scipio

@gipsy_jetsept Nf6 threatens Qh7#. If black were to play gxf6, it would allow Qh6#. There is no way to stop checkmate after Nf6!

gipsy_jetsept

I understand. Thank you.