You can keep an anemone in place by either gluing or stapling it to a rock.
Ok, I'm kidding of course
But there is no guarantee that an anemone will stay put even if happy. I have a single horror story dating back about 2 years maybe? A friend of a former friend of mine had a 90G reef with a BTA in it. It had been in the tank for about three years in one spot; one day, it decided to pick up the family and move. He came home and found quite a bit of dead coral, lost some more the following week, and then lost the BTA as it got sucked into a powerhead.
No guarantees with anemones unless you isolate them, such as in an enclosure inside the tank with proper ventilation. But that would probably be a bad idea as well.