Get Your Sims Married Using the Cheat Code

If you're too lazy to like, build up all the relationship stuff and whatever, this is handy :)

Steps

Ctrl + Alt + C. Now you have your cheat box. Do this in the Neighbourhood.
Type in ' boolprop testingcheatsenabled true '. Without the ' things.
Make / Choose a Sim. This Sim MUST BE AN ADULT. This is the Sim that is going to propose.
Now pick another Sim. This is the Sim that is going to marry the other Sim. It doesn't matter the gender. If you pick two Sims the same gender, they're obviously going to be a gay couple ;)
Introduce your Sims. Just make them talk or something.
Hold down the shift button, and click ' MAKE SELECTABLE ' to your Sim's friend.
Then, on the right side of your screen, click the symbol with two figures holding hands. It's quite small, and this is where it shows your relationships with other Sims.
Under your companion's picture of her / his face, there will be two bars. Again, hold shift, and drag those bars up to 100.
Make them Kiss, and WALLAH! Sorted. They're madly in love.
Click 'Propose...' and 'Engagement...'. HAPPY WEDDING