This is such a silly thing to have to disable, but any time I was using voice to text, it would always put asterisks for swear words. This is on my Google Pixel 3 XL running Android 10 latest update of Feb 2020. The fix was to disable it in THREE spots, not just one, not just two, but all three. The three spots are: Gboard, Google voice typing, and in the text correction section.
Section #1 Google Voice Typing:
Settings > System > Languages & input > Virtual keyboard > Google voice typing and make sure that Hide offensive words is disabled.
Section #2: Gboard
Settings > System > Languages & input > Virtual keyboard > Board -> Voice Typing -> Offline speech recognition and make sure that Hide offensive words is disabled.
Section #3: Text Correction
Settings > System > Languages & input > Virtual keyboard > Board -> Text Correction and make sure that Block offensive words is disabled.
Section #4: UPDATED (Added April 21 2020)
If those three options do NOT resolve it, the 4th option you can use is to disable offline voice: Settings > System > Languages & input > Virtual keyboard > Gboard > Voice Typing > and disable “faster voice typing“.
