Yup~ Let me know what you want spoilers for.
It's a super long process. It takes at least half of the ~1.7k chapters for them to get to romance, though there's plenty of cute fluff and cuddling before then. That's about how long it takes for MC to become 15-16 years old, which is standard 'adult' age for people back then. Then eventually MC and ML sort themselves out and get married. They stay engaged all the way from the start.
The family is selling her off to the dreaded Prince Xiao (AKA ML). Emperor arranged a marriage between their family and the always-a-loner Prince Xiao. Prince Xiao is a war god, rumored to be ugly under his mask (FALSE), and is so violent that no one wants to marry him. The family (actually, I think MC's family is the 'main' family, they usurped the position when MC's dad wasn't quite right in the head anymore) didn't want to use their own daughter for the deal, so they found MC.
Actually, ML didn't want to get married. His dad's a douchebag. ML was going to help MC out, but his subordinates (they wanted to matchmake lol) and circumstances prevented that from happening. ML and MC end up talking things through and ending up engaged. They are super cute and fluffy -- they promise to always be good to each other, trust each other, etc. and ML carries around MC. He also teaches her how to write properly, etc. He even lets her learn martial arts lol. They are super supportive of each other.