My boss asked me if we should continue to give an employee an opportunity to work with us, or fire them, and I wanted to give them employee another chance, now my boss is making me fire them.

We have a coworker who isn’t the speediest at what they do, but haven’t been given the fairest shake. I’ve always been supportive for this employee and have pushed them to do more, while being encouraging. My boss asked me if I wanted to give them another opportunity (they were out for a few weeks, covid) or just cut ties then and there, and I told him we should give them another chance. Fast forward to today and my boss told he wants them fired, and that I need to be the one who fires this person. (I’ve never fired anyone before, this sucks.)