A lover who can't say what he feels in daylight invites his beloved out after dark. That is the whole situation, and the poem makes a small drama out of it. The speaker proposes two walks, one to a twilight grove and one to a restless sea. Along the way we learn why he needs the night: his feelings are far less gentle than his courtly language suggests. The central idea is the gap between the calm surface a person shows and the turmoil underneath, and the poem lets the landscape voice what the speaker keeps back.
The form is simple on purpose. Each of the six stanzas has six lines and rhymes *aabccb*, so every stanza closes on a rhyme that echoes the third line: "bright" with "daylight," "nigh" with "sky," "steep" with "leap." The lines are short, mostly two beats, with a longer third and sixth line that lengthens the pace for a moment. The result is a lilting, almost waltzing rhythm: "Shall we roam, my love, / To the twilight grove." It sounds like a whispered invitation, which suits a speaker who plans to whisper.
The imagery divides into two worlds. In the grove everything is cool and pale: "cool night-air," "pale moonbeam," "silver sheen," "the cold ray." Even the beloved's beauty is described in the language of light. It is "more bright / Than the stars' soft light" and "a weft from the sky," as if she were woven from the heavens. The word "weft" is a good choice, since it makes her seem delicate and made of threads. The repeated "cold" and "cool" are worth noticing, though, because the speaker is anything but cold. The moon is simply the setting where he feels brave enough to speak.
At the fourth stanza the poem changes. The grove gives way to the sea, and the sounds turn violent. The waves "toss and roar and leap," the sea is "boiling," and "the storm … raves." These verbs belong to a fight, and stanza five says so outright. The waves "resemble the strife / That, from earliest life, / The passions have waged in my breast." Until then the speaker has only hinted at his feelings. Now the metaphor of war explains everything. The "queen of my heart" in the title is also a battlefield, and the throne she sits on is shaken by the conflict. Her face lit by the cold moon and the speaker's boiling inner sea are two halves of one picture.
The refrain-like framing is clever. The last stanza nearly repeats the first, but the changes matter. The tentative "Shall we roam?" has become the firmer "Oh, come then, and rove," and the speaker now offers the sea or the grove, whichever she prefers, so he has taken in both sides of himself. The final line also loses its exclamation mark. "What I dare not in broad daylight!" first sounds breathless and almost playful. The same words with a full stop sound resolved and more serious.
There is also a quiet irony. The speaker promises to whisper what he cannot say by day, and he also says he will tell only "a part" of his thoughts. Yet the poem has already told us the larger secret, that his passions are a storm. We hear the whisper before the lovers have even left. We are never told the exact words he will say, so the poem keeps its secret and gives it away at the same time.
Some of the phrasing is conventional. "Heart's throned queen" and "thy beauty" belong to a well-worn vocabulary of devoted love. Even so, the poem has a clear and appealing design. It pairs a moonlit stillness with a roaring sea, so that a feeling too big for ordinary talk becomes something the reader can see and hear. Its significance lies in that pairing. Love here is both a tender light on a face and a long struggle in the chest, and the poem's closing repetition suggests that the speaker is still waiting for night to give him the courage to say so.