To add to another answer that addresses the other poem, in “Impromptu II: To a Lady” Alexander Pope represents most women as having bad character. The second line of the first stanza says, "Most women have no character at all." His overall strategy is to satirically point out the weaknesses of women, and insodoing, try to instruct his readers to not be like the vain, unreasonable, and dispassionate women he talks about, but to try to be the exception.
Pope begins to satirize women as vain by discussing beautiful women in portraits. Arcadia’s Countess displays “ermin’d pride,” or pride in her dress. Ermine skins were used for royal clothing, so this is a way to say she is vain in her display of wealth. Fannia is “leering” at her man in her painting, which means she is looking with an unpleasant expression upon him; in other words, she is lacking a good character, and it shows on her face. A little farther down, Silia frets over a pimple that has shown up on her nose, which is considered silly. Pope satirizes the painting of these beautiful women as “Folly grown[n] romantic," or foolishness that has come to idealize women despite flaws in inner and outer beauty.
Pope also mocks women as lacking the ability to reason. He says “Papilla,” or a beautiful butterfly of a woman, will long for shade but then complain about the trees that provide the shade. He also returns to Greek myth by referencing Calypso, who was able to trick Odysseus into staying on her island for a long duration. But he does not attribute her success to beauty, charm, or wisdom. Rather, he says it was due to mimicry of what men would really admire and deceitfulness, or wit:
'Twas thus Calypso once each heart alarm'd,
Aw'd without Virtue, without Beauty charmed;
Her tongue bewitch'd as oddly as her Eyes,
Less Wit than Mimic, more a Wit than wise;
Finally, Pope attacks women who do seem perfectly beautiful and virtuous through his discussion of Chloe, or Demeter in mythology. He says,
Yet Chloe sure was form'd without a spot—"
Nature in her then err'd not, but forgot.
"With ev'ry pleasing, ev'ry prudent part,
Say, what can Chloe want?"—She wants a Heart.
She speaks, behaves, and acts just as she ought;
But never, never, reach'd one gen'rous Thought.
Virtue she finds too painful an endeavour,
Content to dwell in Decencies for ever.
So very reasonable, so unmov'd,
As never yet to love, or to be lov'd.
In other words, Chloe seems to be the ideal women with unblemished beauty, prudence, ability to reason, but it is all for naught because she lacks a heart or passion. Chloe is able to go through the gestures of love and faithfulness and virtue, but there is no conviction behind it, which makes her reprehensible as well.
Probably the most interesting reference is to Sappho, who was not a Greek myth, but a Greek lyrical poet who was female. Unable to attack her artistic brilliance, he simply points out the temporality of her career by comparing her to an insect that is “flyblown” by sunset, as if she was unable to make a “lasting impact” on history. This is interesting as the sexist world tried for a time to erase Sappho from history by destroying her works, but her brilliance has been resurrected again and again across the eras, even recently when more pieces of her poems were discovered.
All in all, while this is a satirical poem, it was meant to instruct women, and telling a woman to try to be unlike the rest of her sex by trying to have good character is belittling and reflects the sexism of a moment in history.