How did they meet?
Chibi-Usa was walking down the mall when suddenly she bumps into this boy coming out of Sun Coast. They both say their apologies to each other, and introduce themselves. The boys name was Trunks.
What happened afterward they met?
Trunks invites Chibi-Usa to some ice cream at a close by ice-cream shop. They both get rocky road in a cone. Later on after the ice cream they take a stroll on the park and get their first kiss from each other. They say their goodbyes and headed for home, but before they say goodbye they make a deal to meet every afternoon or night at the park. Both sets of parents where waiting for their kids to get home. The more Bulma and Vegeta, and Serenity-sama and Endymion-sama waited for each of their children to get home, they got madder by the minute.
When Trunks and Chibi-Usa finally got home they went inside to find each of their parents on the couch being madder than ever. When they tried to explain what had happened the parents where to mad to listen so they got grounded. Since they where grounded they both had to find a way to sneak out and sneak calls by the mad parents at night. It was harder for Trunks since Vegeta could sense him. It doesn't matter much because they managed to sneak out and if they couldn't sneak out they would call each other art night and get the calls past their parents.
Marriage?
After dating for many years they did get married. The year after getting married they had twin boys and after the boys arrived they had twin girls making the boys a year older than the girls. They both died of old age, Chibi-Usa died first then years after Trunks died.