YOU SAID:

loud farts are not stinky but quiet farts are very stinky

INTO JAPANESE

うるさいオナラは臭くないが、静かなオナラは非常に臭い

BACK INTO ENGLISH

Noisy farts do not smell, but quiet farts smell very

INTO JAPANESE

うるさいオナラは臭いませんが、静かなオナラは非常に臭いがします

BACK INTO ENGLISH

Noisy farts do not smell, but quiet farts smell very