The word quarantine can be a little confusing to say.

The dominant stress is on the first syllable, and the secondary stress  is on the last syllable. Not everyone says it in exactly the same way, but this is the general pattern:

 ˈkwɔɹ  ən   ̩tin

or

 ˈkwor  un  ̩teen

Historical Tidbit

The word quarantine comes from the Italian "quaranta giorni", meaning "forty days". During the Black Death plague epidemic in the 14th-15th centuries, all ships arriving in Venice were required to be isolated for 40 days before anyone could go ashore.