Everyone who's ever heard me say this for the first time starts shouting and disagreeing with me.
Then they try it. And then they stop shouting.
On a bass, a note is essentially a box bordered by frets. Each box looks no different from every other box, and it can seem completely random. The idea of assigning a different note name to each box can be very intimidating to someone who doesn't know any music theory.
The only instrument on which you can truly visualize all the notes in a way that they don't get confused with other notes is the KEYBOARD. People who study theory only on a bass or guitar neck seem to work very hard at memorizing the locations of all the sharps/flats, but piano and keyboard players think it's the easiest thing in the world, because it's laid out so easily on the keyboard... they get "White" and "Black" keys... all the white keys are natural notes, and all the black ones are sharps/flats.
I'm not telling anyone to go take piano lessons (although I'm not telling you not to...) but I am saying that learning how the notes are arranged on a piano keyboard makes way more sense than a fretboard, and once you've learned where the sharps and flats are, you'll never forget it.
You don't need a keyboard to do it (although it certainly helps). All you need is a diagram of one.