Dalilahshigaraki's poem starts with a question: when people say "I love you," what do they actually mean? The speaker points out that the words can become a habit, something said as casually as hello or goodbye. Then they set out to show what the phrase means when they say it.
The answer comes in two parts. First, a long list of small, specific things the speaker loves: a laugh, a voice, hands, even the way someone doesn't sigh on seeing them. Many of these are about how the other person treats the speaker, not just how they look. The list ends with the playful, tender "I love your you," which suggests love for the whole person. Second, the speaker defines the words as a promise: to protect, to listen, to stay.
The mood is earnest and warm, with a note of vulnerability. The speaker loves "all the way, or not at all," and the closing question hands the idea back to the reader.