What message do you think Lady Macbeth wants her fainting spell to convey in Macbeth?

Lady Macbeth faints when the death of Duncan is announced by
Macduff.  We know that she planned the murder.  By fainting, Lady Macbeth, does what she thinks
she should do.  Remember, she asked to be unsexed so she could plan the murder of the king, but
since she is a women, she must play the feminine role.

Lady Macbeth
also uses the faint to divert attention away from the death of the king and Macbeth's murder of
the two guards.  Of course Macbeth kills them so they can't be questioned about the murder of
Duncan.

Lady Macbeth knows how to be the "innocent
flower".