Instructions
Get to know the Sims in your town. When you find one you like, chat with him or her regularly. As you interact with a Sim, your relationship level will go up. You'll reach the Acquaintance level first, followed by Good Friend.
Choose romantic options when interacting with the Sim, such as Dance, Be Romantic or Kiss Cheek. When you use these options, your relationship level will progress to the Best Friend, Budding Romance, Date and Partner level.
Keep acting romantic once you've reached the Partner level. When you can't raise this level any higher, you get the option to propose to the Sim. You can also ask the Sim to move in with you now or wait until after the wedding.
Talk with the Sim and select the "Propose Marriage" option when it becomes available. Choose a ring for the Sim. If the Sim doesn't like the quality of your ring, he or she won't accept the proposal. The best ring you can buy is the Eternity Ring for 20 Life Points. If the Sim accepts your proposal, you'll get engaged.
Chat with the Sim again and select "Ask to Move In." Once the Sim has moved to your house, use the "Be Romantic" option until your relationship status changes to Married.
Enter Build Mode and go to the Nursery section. Buy a crib and place it anywhere in your home.
Tap the crib to create your baby. Give the baby a name and then select a gender and skin tone. Your new baby will appear in the crib.