My mac keyboard print ˜ instead of ~ when I press delta key a ˜ instead of ~, I have to hit space every time after printing ˜ to get ~.

How to print ~ directly without clicking space after it?

my system is Mojave 10.14.4
my keyboard is U.S. International - PC
Get rid of “us international pc” and use “us”or “abc” instead.  You do this in system preferences/keyboard/input sources.