Where have you landed them previously? Take it to grass before concrete. If you totally bail and land on your head or back or something then yeah, hurts a lot more on concrete and can cut you up. But if you land on your feet poorly it's just more impact to take, not honestly that much worse than grass. I'd actually rather side flip on concrete because it's easier to jump on than grass.
To get over the fear I flipped off of concrete onto grass. So just off a sidewalk or something. When I got comfortable with that I knew there was no functional difference and just flipped on concrete. It's really scary at first but with some practice you'll get comfortable to the point where you don't even care what substance you're flipping on.