It sounds peaceful and in love. We'd definitely like to have what the speaker is having. At the same time, though, it's not as if "[i carry your heart with me(i carry it in]" sounds like some lovesick puppy pulling petals off a daisy. Cummings is way too cool for that. Instead the poem sounds balanced, precise, with only a light dusting of romantic clichés to give it that love-poem kick. The speaker's casual tone and use of ambiguity ("whatever," "anything") also keeps us from rolling our eyes over a bunch of overused metaphors and hyperboles that we usually hear in love poems.
Notice how we're not overrun with adjectives to describe his lover's ruby cheeks or flowing hair. Instead we've got ultramodern lines like, "you are whatever a moon has always meant." So Cummings is keeping things real for us while still managing to create a flutter in our tummies with lines like, "i fear no fate(for you are my fate, my sweet)." The combination of the ultramodern with the occasional romantic cliché adds to the poem's balance and freshness in the world of go-to love poems.
Cummings also avoids bombarding us with perfect couplets that would make his poem sound a bit too song-like for a modern audience. Instead he uses syntactical patterns ("i go," "you go") to create a noticeable rhythm that doesn't get annoying like some rhymes might.
Internally we do notice some alliteration that adds to the poem's lyrical and organized sound. For instance lines 3-4 have a repetition of that D sound in "dear," "done," "doing," and "darling." In the second stanza, we have the repetition of that F and W sound in "fear" and "fate," and "want," "world," and "whatever." So it looks as if Cummings was aiming to create an organized and uniform sound for each stanza without going overboard with too many cute couplets.