nm, Below ppl explained to me how to do it
Oh thank you. That does work. Kinda weird that some options aren't in the advanced brush controls, so I kind of ignore them.
I'm pretty sure someone probably said this once before to me a few years ago but I forgot. I tended to switch to other programs for a really clean line, but painter seems capable of doing it then.
Anyway, this was the result, overdid it but it works well. So it's not a good suggestion anymore then, since we can already do it.
It looks like this doesn't work when using different brush sizes, when reducing the size to 2 pixels for details, for example, it's back to pixelated again. Honestly, they just need to add anti-aliasing to the program. What's the use of having so many brushes, that can blend in incredible different ways.. all ruined with jagged edges.. Honestly... this problem is such a waste for the program.