The poem is a dramatic monologue, meaning it's written in the voice of a character who's not the poet. In this case, the speaker is a woman whose male partner—a suitor or husband—has been unfaithful to her. ("A Song of Faith Forsworn" means, roughly, "A Song of Falsely Promised Fidelity.")
The exact nature of their relationship, and his betrayal, is somewhat unclear. Has she learned of his infidelity before marriage or after? Has he been sexually unfaithful, emotionally unfaithful, or both? Whatever the exact situation, there's no evidence in the poem to suggest that she's wrong about her partner. The poem is framed as a righteous reproach, in which she tells him to "Take back" everything he gave her, then rejects him for good.
In this first stanza, she specifically commands him to "Take back [his] suit." Here, "suit" means a formal appeal to begin courting a woman—a standard part of the courtship process in the Victorian era, when this poem was written. (Typically, a "suitor" made the appeal to the woman's father.) The speaker explains that she accepted her suitor's courtship only because she was "weary and distraught / With hunger" for the "food" of love. She suggests that, in her desperation, she would have accepted "any food" at all. Extending the metaphor, she protests that she had no way of "guess[ing]" what kind of "fruit" his love represented and that when she so much as "Nibbled" it, she found it awful.
From the start, then, the speaker heaps scorn on a man she considers a villain. She never really loved him, she implies; he just tricked her into thinking she did, because he preyed on her when she was weak. She never completely fell for him; she just "Nibbled [the] edge" of the love he brought, as if tasting a new "fruit," and even that small taste was disgusting.
- The speaker may be alluding, here, to the Adam and Eve story, in which Eve—tempted by a wicked serpent—eats the forbidden fruit from the Tree of Knowledge of Good and Evil. If so, the implication is that her male partner is as wicked as the serpent and has taken advantage of her innocence. (The phrase "nowhere found it good," in line 5, may imply that his "love" is actually evil!)
Structurally, this first stanza also establishes a pattern that will continue throughout the rest of the poem:
- The opening line is a terse instruction to "Take back [something]," which is then repeated in the final line of this stanza.
- The four middle lines, meanwhile, expand on the instruction, providing context or explanation, before it's repeated.
- The first and sixth lines are set in iambic dimeter (meaning they consist of two iambs, or metrical feet that follow a da-DUM rhythm), while the middle four lines are set in iambic pentameter (which simply means they consist of five iambs).
- Finally, the rhyme scheme of the stanza as a whole is ABBCCA. This symmetrical structure sounds emphatic and authoritative, as the speaker commands, explains, then commands again.