The poem is a string of questions, and none of them gets an answer. It begins by wondering whether the body, imagined as a book, holds any writing as true as romance. The speaker seems to place love at the center of what the body can tell us.
Then comes a strange, unsettling image: two children perfectly made, joined at the belly, sharing one pair of legs. Asking which of them is "true and which false" suggests that something about closeness, or about being one person or two, resists easy sorting. Judging by the imagery, the speaker may be thinking about how lovers can feel fused together.
The last two questions turn more tender and more uneasy. The speaker asks what could make us fear the consequences of love, then ends with wonder: holding you feels like "so large a music." The mood is hushed and curious, with fear and awe sitting side by side.