You have it in a pen where it can't actually see you, you have put fud in there for it. A stack of carrots will do with some razzle dazzle berries for dessert and then you hang about within 60 meters till tamed. Takes a couple in game days. No fires of any kind around them. Eventually you will see a green heart beam out of them and that shows they are in the taming process. If you leave the area, it stops. If they get scared again not sure what it does but not helpful. I had one boar that never would tame so I killed it and started over. The next one was fine. Do not show yourself to them until their bar is green.