People who are learning English like to pronounce the word ‘course’ like ‘curse’ probably because of the Portuguese word ‘curso’.
Course rhymes with horse, and curse rhymes with worse.
(Course rima com horse, e curse rima com worse. )
Course (aula) sounds exactly like coarse (grosso).
The vowel in ‘course’ has the same sound as in the word ‘or’ .
To have an English course is a good thing.
To have an English curse (maldição) would be a bad thing.