How to tell parents u fail a class?

Have them sit down together and tell them that you
failed a class because of ..............(be truthful as to the reason);
but, that you know you can do better in the future and with
their full support and love you know that this will never happen again.

Just tell them the truth, and take your medicine.

show them ur progress report and have them sign ur progress report.
or have ur teacher call ur parents that ur failing a class