The speaker tells someone they live deep inside the heart, the way an oyster rests under the sea. Love is the pearl that slowly grows there, getting more beautiful and bright with each passing day. It sounds tender at first, even proud.
Then the tone shifts. The poem remembers something about oysters: a pearl is made at the oyster's expense, and getting it out can mean the oyster's death. The speaker sees the same fate for themselves. The love that grows so beautifully inside them may one day be what destroys them. The broken, hesitant lines, with all their dots and pauses, make it feel as if the speaker is trying to say something painful and keeps losing their nerve.
The last word, "Yet...", is the heart of it. It's left hanging. The speaker knows the danger but does not say they will give up the love. The mood is quiet, sad and resigned, with a stubborn devotion underneath: loving fully, even knowing the cost.