The Love Tub is an aspiration reward that was added in The Sims 2. It's a hot tub with candles around the rim to give it a romantic feel. It is meant to increase relationships among Sims. Sims can do anything in it that they can in an ordinary hot tub, but while the candles are burning, social interactions between Sims in the tub are more likely to be accepted, and will have a larger effect. It has been reported that, if Sims "Try for Baby" while the candles are burning, it is more likely to result in a pregnancy. Getting a Love Tub will fulfill the want to buy a hot tub.