Going by the numbers on the What-if blog, Shah Rukh Khan and Madhuri Dixit sure had it easy in Dil To Pagal Hai:

The odds of running into your soul mate are incredibly small. The number of strangers we make eye contact with each day is hard to estimate. It can vary from almost none (shut-ins or people in small towns) to many thousands (a police officer in Times Square). Let’s suppose you lock eyes with an average of a few dozen new strangers each day. (I’m pretty introverted, so for me that’s definitely a generous estimate.) If 10% of them are close to your age, that’s around 50,000 people in a lifetime. Given that you have 500,000,000 potential soul mates, it means you’ll only find true love in one lifetime out of ten thousand.