This was written by John Keats around November 1817. If he is referring to a specific person, she is not known.

Think not of it, sweet one, so

Think not of it, sweet one, so;
Give it not a tear;
Sigh thou mayest, but bid it go
Any, any where.

Do not look so sad, sweet one,
Sad and fadingly;
Shed one drop then--It is gone--
Oh! 'twas born to die.

Still so pale?--then, dearest, weep;
Weep! I'll count the tears;
And each one shall be a bliss
For thee in after years.

Brighter has it left thine eyes
Than a sunny hill:
And thy whispering melodies
Are tenderer still.

Yet, as all things mourn awhile
At fleeting blisses,
Let us too!--but be our dirge
A dirge of kisses.