Let me not to the marriage of true minds
Admit impediments. 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 wandering bark,
Whose worth’s unknown, although his height be taken.
Love’s not Time’s fool, though rosy lips and cheeks
Within his bending sickle’s compass come;
Love alters not with his brief hours and weeks,
But bears it out even to the edge of doom.
If this be error and upon me prov’d,
I never writ, nor no man ever lov’d.
In plain English
Don't ask me to list reasons why true love might fail. Real love doesn't change when circumstances change, or bail when the other person leaves. It's a fixed landmark, unmoved by storms; a guiding star for anyone lost at sea, its value immeasurable even if you can plot its position.
Love doesn't serve Time's purposes, even though beauty fades—time's sickle cuts down youth and color. Love itself doesn't shift with passing hours and days. It holds steady all the way to death itself.
If I'm wrong about this, if you can prove me wrong, then I've never written a true word and no human has ever really loved.