Step 1: ten hearts
Reach 10 hearts with your chosen villager through gifts, daily conversation and heart events. Buy a Bouquet from Pierre’s (100g... at the shop counter) once at 8 hearts to start dating — bouquets unlock hearts 9 and 10. Keep the gift loop going: decay never fully stops.
Step 2: the Mermaid Pendant
At 10 hearts, the Old Mariner appears on the rainy beach (east side, past the bridge) selling the Mermaid Pendant for 5,000g. Give it to your partner to propose; the wedding is three days later. The pendant only appears in the rain, so plan around the weather forecast and keep the cash ready.
Married life and the upgrades
Spouses move in, water crops and feed animals some mornings, cook random breakfasts and dinners, and add a personal room. The two relevant house upgrades: the kitchen (cooking — required for many recipes) and the nursery (crib room after marriage). Outdoor decor, pet adoption and the spouse’s outdoor area decorate themselves over time. Friendship still decays slowly — gifts still matter after the wedding.