How do you get 2 sims to get married on Sims

you have to build their relationship to a very high romantic one and then one sim has to propose to the other. if that option is not available, then the relationship is not high enough. once the sim proposes, then they will be "engaged" to get them married, you can do one of two things.
- buy the wedding arch and click that
- just click the person and select propose > marriage hope that helps!