Can I legally evict someone from a house I have 50% ownership in, if the other owner wants them to stay?

If you have a fractionalized ownership interest in a home that you are renting where you want to evict a tenant but the other owner does not, you can still go ahead with the eviction process. A problem will arise if the other owner intervenes to try and stop the eviction of the particular tenant that you are writing about. The result is that the court would then most likely deny the eviction if that happens.

If the other owner does not intervene to stop the eviction of the tenant that you are writing about, then there is a chance that the eviction will be heard on its merits by the court.