How do i kick out a sim i originally asked to move in?

First u may be able 2 become enemies with the sim u wanna kick out, u might be able 2 kick them out after so many negative interactions. I never tried it, just an idea.
Now what i know will work is to use ur cell phone 2 'move out.' From the move out screen you'll be able to choose which sims will remain in ur household. If you choose to do this, you will permanently delete that character so don't say i didn't warn u. =p From there just move back 2 ur same house minus the sim you've kicked out, and don't sell ur place furnished if u like ur stuff =)

Become enemies with them until the option appears kick out or something like that.

I had a similar problem. I built a small building with a rug and two fireplaces, and lit them both. Eventually they died. Extreme, but quick and effective. Never knew it was possible to kick people at that time though!

Select the 'move' option on your phone, and there will be a list of all the sims which you can move to another household, keep all of the sims you want to keep where they are, and move the one you want to kick out.