The best book, Bear Attacks, with a research basis, even though published long ago says there is always the possibility a rogue black bear is predatory. However, the bluff is their M.O.
So, if you attempt to discourage one and they come back a second and third time, bluff or not, you would be well advised to empty everything you've got into suspect if you have a modicum of survival instinct or will to live..
Yah, the chances are miniscule you will become a statistic, but you don't want to be writtten up in a book as your last will and testament of bear attacks.
Cats like to chase, bears will chase, if you want to be in a footrace with a predator, run! Chances are you will lose. But sometimes a chance chanced is your only ticket!
When in doubt, get the best bear spray you can as a first line, and like said in many threads before, practice with it..
And, though I do it all the time, don't hike alone, hike with somebody slower than you, j/k