Read the following passage spoken by juliet.

yet i should kill thee with much cherishing.
good-night, good-night! parting is such sweet sorrow!
that i shall say good-night till it be morrow. (ii. ii. 200-202)

of what motif is it an example, and how do you know?

oxymoron; it does not make sense, but it is true anyway.
oxymoron; sweet is not a word that one would typically use to describe sorrow.
symbolism; the parting is symbolic of their ultimate deaths.
dramatic irony; the reader already knows what is going to happen.