You will probably find that William Shakespeare never actually wrote these lines. He did however, write some really rather good ones about the subject love - here are some off the top of my head:
Love looks not with the eyes, but with the mind
And therefore is winged Cupid painted blind
(A Midsummer Night’s Dream – I.1)
O brawling love! O loving hate!
O anything of nothing first create!
O heavy lightness, serious vanity
Mis-shapen chaos of well-seeming forms
Feather of lead, bright smoke, cold fire, sick health!
(Romeo & Juliet - I.1)
Benedick A miracle! here’s our own hands against our hearts. Come, I will have thee; but, by this light, I take thee but for pity.
Beatrice I would not deny you; but by this good day I yield upon great persuasion, and partly to save your life, for I was told you were in a consumption.
(Much Ado About Nothing V.6)
And the best one,
Cleopatra If it be love indeed, tell me how much.
Antony There’s beggary in the love that can be reckon’d.
Cleopatra I’ll set a bourn how far to be belov’d.
Antony Then must thou needs find out new heaven, new earth.
(Antony & Cleopatra I.1)
Not bad, eh? Not to mention this one:
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 proved,
I never writ, nor no man ever loved.