Answer:
Paradox
Step-by-step explanation:
A paradox is simply a word that seems contradictorily untrue or opposite in meaning but on closer inspection, elements of truth can be discovered in it.
The lines "These violent delights have violent ends/And in their triumph die, like fire and powder,/Which, as they kiss, consume" shows contrasting ideas which seem contradictory at first such as violent delights have violent ends and in their triumph die, as they kiss, consume.