I live in New Jersey and my Mother-in-law has lived with me for the last five years. I met a woman whom I plan to marry so I want to move on with my life. Can I legally get her to leave?

Sure you can, you just can't "kick her out". You have to go through the legal process. This means giving her 30 days notice to vacate. If she doesn't vacate, you have to take her to court for an eviction order.

Since you have apparently been subsidizing her living, why not arrange for her to move into an assisted living center and you can pay for part of it. Seems better than evicting an 82 yr old.

Do you own or rent this property?

Why hasn't she been on a waiting list for senior housing? Did your ex die or disappear or what? I don't get evicting an 82 year old, no matter what the relationship. Start with the town social worker. Look in the blue pages or call the main city hall number.

This question is begging for more detail. How did her living with you come about? Has she been paying anything toward the management of the house? Do you claim her as a dependent?
Why do have to "legally" get her out? Has she refused to move on her own? If yes, why?

Is there a reason your ex can't take her mother in?