The speaker is in love, and the poem is a list of the moments that prove it. Each short stanza offers a picture, such as holding hands, smiling, kissing, or hearing a voice, and each one ends with the same plain line: "Am happy." The speaker never says more than that, and the repetition makes the feeling seem simple and certain.
The pictures also narrow as the poem goes on. It begins with shared actions between two people, then moves to "his face" picked out of a crowd and "his voice" in a silent room. By the last stanza, all that is left is "Him / In front of me." The world shrinks until only one person matters. The dropped "I" in "Am happy" gives the lines a quiet, almost breathless tone, as if the speaker is too full of the feeling to bother with full sentences. The mood is warm, calm and content, with no doubt in it.