This fare is available for departures on Tuesdays and Saturdays, with return flights open on Mondays, Thursdays, and Saturdays. The travel window available for flights at this price is from August 15 through September 29, 2018.
Searching on LATAM's website, I was able to find seats departing MIA on Saturday, August 18 and returning from FOR on Monday, August 27, 2018.
Starting earlier this year the Brazilian government has made it a lot easier to visit, with the introduction of an E-Visa program which you can read more about here.
Have a look at all our current finds from Miami (MIA) on its very own flight deal page.
Need a room in Fortaleza? Here's a list of all available accommodation for the dates mentioned on Hotelwatchdog.