To Ophelia

Doubt thou the stars are fire,
  Doubt that the sun doth move,
  Doubt truth to be a liar,
  But never doubt I love.
 O dear Ophelia, I am ill at these numbers. I have not art to reckon my groans, but that I love thee best, oh, most best, believe it. Adieu.
  Thine evermore, most dear lady,
  whilst this machine is to him,
    Hamlet.
–William Shakespeare

Sonnet 18

Shall I compare thee to a summer’s day?
Thou art more lovely and more temperate:
Rough winds do shake the darling buds of May,
And summer’s lease hath all too short a date:
Sometime too hot the eye of heaven shines,
And often is his gold complexion dimm’d;
And every fair from fair sometime declines,
By chance, or nature’s changing course, untrimm’d;
But thy eternal summer shall not fade
Nor lose possession of that fair thou ow’st;
Nor shall Death brag thou wander’st in his shade,
When in eternal lines to time thou grow’st;
So long as men can breathe or eyes can see,
So long lives this, and this gives life to thee.

Sonnet 15

When I consider everything that grows
Holds in perfection but a little moment,
That this huge stage presenteth nought but shows
Whereon the stars in secret influence comment;
When I perceive that men as plants increase,
Cheered and check’d even by the selfsame sky,
Vaunt in their youthful sap, at height decrease,
And wear their brave state out of memory;
Then the conceit of this inconstant stay
Sets you most rich in youth before my sight,
Where wasteful Time debateth with Decay
To change your day of youth to sullied night;
And all in war with Time for love of you,
As he takes from you, I engraft you new.
–William Shakespeare

Sonnet 116

Love is not love
Which alters when it alteration finds,
Or bends with the remover to remove.
O no, it is an ever-fixed mark
That looks on tempests and is never shaken;
It is the star to every wand’ring bark,
Whose worth’s unknown, although his height be taken.

― William Shakespeare