You will need to make sure they are in the same server as you. To marry a user, you will need to run
n!marry <user>. Once you do so, a dialog will be sent for the other user to confirm. They will be pinged to make sure they are well and truly aware that you want to marry them!
If they say Yes. Then you are now a couple, congratulations!
Now, you can check the marriage status with
n!marriage <user> The embed will display information such as who you are married to and the date you got married.
To divorce a user, run n!divorce <user>. The following dialog will be sent to confirm this.
Specifying Yes will result in all of your marriage data and the other user's marriage data to be wiped. Thus resulting in you becoming single.
You will need to let us know if there is an inactive user or you cannot legitimately divorce a user. Please see this guide on what to do if that happens!