O, swear not by the moon, th’ inconstant moon,
That monthly changes in her circle orb,
Lest that thy love prove likewise variable.

Orsino: For, boy, however we do praise ourselves,
Our fancies are more giddy and unfirm,
More longing, wavering, sooner lost and won,
Than women's are. ...
For women are as roses, whose fair flow'r
Being once display'd doth fall that very hour.
Viola: And so they are; alas, that they are so!
To die, even when they to perfection grow!

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."

(Sonnet 116)

Love is not love which alters it when 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."

(Sonnet 116)

Oft expectation fails, and most oft where most it promises; and oft it hits where hope is coldest; and despair most sits

Women are never tired of bewailing man’s fickleness in love, but they only seem to snub his constancy.