How do I stop being too nice so that people don't use me?

I let my old coworker stay on my couch because him, his 2yo & his girlfriend (not baby mom) were getting kicked out of their place and he had burned bridges with his family and with hers. I asked him for rent, he knew about it in advance, and he said Friday, Friday comes and he says Sunday. I told him I really needed the money, he said he has other bills and that I know he lost his one job and was just getting paid from his new job. I told him he wouldn't have lost his very good job had he went to fucking work for the week, not blamed covid, not been up at the bar every night getting trashed because him and his lady broke up. He took all his shit and owes me $400 because I was "mean" and didn't want to listen to his piss-poor excuses. I let him stay on my couch and he had not done one thing to help around the house. He has a daughter but was too upset to make money and support her. His parents literally live 2blocks from me, but he did something to burn that bridge, so he was living here. Him and his then lady came to my house and asked if he could stay and it's so hard to tell people no when they're right in front of you, they messaged me, even, to ask if they could stop by to ask me a question, so they knew what they were going to ask. He took advantage of the situation.
I'm a good person, if you really need a place to stay I am more likely than not going to tell you no, but there are some conditions ie help clean, help with the outside, be a functioning member of the household!
I need to stop being so nice, any ideas?
How do I stop being too nice so that people don't use me?
Add Opinion