Sappho's fragment 31 enacts this dramatic movement:
he seems to me equal to gods that man
who opposite you
sits and listens close
to your sweet speaking
and lovely laughing -- oh it
puts the heart in my chest on wings
for when I look at you, a moment, then no speaking
is left for me
no:tongue breaks, and thin
fire is racing under skin
and in eyes no sight and drumming
fills ears
and cold sweat holds me and shaking
grips me all, greener than grass
I am and dead -- or almost
I seem to me
The poem begins as a description of her friend and her friend's lover, with a hint of erotic desire, but by the fifth line with its exclamatory "oh" the speaker becomes focused only on the girl and herself. She moves from the metaphoric heart on wings to the more physical "tongue" and more insistent sense impressions of "fire" and "drumming" to the "cold sweat" and "shaking" of the last stanza. She is, in other words, gradually overcome. Certainly jealousy, as Carson and others point out, is the root cause here, but what sets the last three stanzas off is the quick move in stanza one from the man to "you" and her "sweet speaking" which links the girl to the sweet speaking of the narrator through her poem. The erotic situation is resolved poetically by a sense of utter loss as death, but remains unresolved, in constant tension in terms of the dramatic situation. And we can add that the poet Sappho adds a kind of fourth figure here, who understands what the speaker is going through and takes a sort of erotic pleasure in that, in her own 'sweet speaking," just at Neruda takes an erotic pleasure in the sad lines of his own poem. The author, in a sense, takes a vicarious pleasure in the speaker's situation:there is always an ironic context that serves to heighten the tension.
http://www.utc.edu/Academic/English/pm/eros.html