Is there another letter? What should it say?

Lear:

There is no other letter if you have none.
(Reading)
"Open your window when the moon is dead,
And I will come again.
The men say everywhere that you are faithless ...
And your eyes shifty eyes. Ah, but I love you, Gormflaith." ...
This is not hers: she'd not receive such words.

Goneril:

Her name stands twice therein: her perfume fills it:
My knife went through it ere I found it on her.

Lear:

The filth is suitably dead. You are my true daughter.

Goneril:

I do not understand how men can govern,
Use craft and exercise the duty of cunning,
Anticipate treason, treachery meet with treachery,
And yet believe a woman because she looks
Straight in their eyes with mournful, trustful gaze,
And lisps like innocence, all gentleness.
Your Gormflaith could not answer a woman's eyes.
I did not need to read her in a letter;
I am not woman yet, but I can feel
What untruths are instinctive in my kind,
And how some men desire deceit from us.
Come; let these washers do what they must do:
Or shall your Queen be wrapped and coffined awry?

She goes out by the garden doorway.