The speaker describes someone who has a “woman’s face,” implying that this person has features that are traditionally feminine, delicate, and soft. The speaker then compares this person’s face to a painting made by “nature’s own hand,” suggesting that this person’s face is not only graceful and feminine, but also as beautiful as a work of art. By personifying nature as someone with a “hand” who “painted” this face, the speaker further suggests that nature took the time to make this person particularly beautiful.
In the second line of the poem, it becomes clear that the speaker is addressing this beautiful person directly. “Hast thou,” the speaker says, a phrase that translates in modern English as “you have.” After the enjambment at the end of the first line, then, the speaker reveals that he is speaking directly—and even, perhaps, privately—to the person with these beautiful, feminine features.
The speaker then goes on to identify this “you” as “the master-mistress of my passion.” The phrase “master-mistress” suggests that this other person is both “master”—a male term for a lord or ruler—and “mistress”—a word that can refer to a female “master” but also to a lover or wife. The hyphen, combining the two words, implies that the object of the speaker's affections is both masculine and feminine. At the same time, the phrase suggests that this person has a kind of power over the speaker (as a “master”) and is the speaker’s lover or intimate partner (his “mistress”).
The word “passion” is important here, simultaneously implying strong feeling, love, and desire. This beautiful person, then, who is both masculine and feminine, is a kind of “lord” or “lady” of the speaker’s own “passion”—the singular focus of the speaker’s love and attraction.
Sound links all three words together. First, alliterative /m/ sounds connect “master” and “mistress,” emphasizing that this person encompasses qualities that are both masculine and feminine. Consonant /st/ sounds further link these words together. Then, the /ah/ sound of “master” repeats in “passion,” reinforcing the connection between the two words and the power that this person has over the speaker’s desire and love.