A formal proposal.
A formal proposal is something very common in most noble families. It was a festive event where the groom would take his parents to the house of the potential bride to formally propose marriage in front of their peers. Before this, the groom would send a bride price to the bride's family.
The bride's family could accept the gift but still refuse the proposal. If this happened, the groom would have no choice but to go home with his family.
To avoid this, it was advised that the groom and potential bride should spend time together and establish a relationship before they decide to have a formal proposal. However, since the nobles like to follow rules and enjoyed shaming someone for being promiscuous if they somehow break these rules, the couple can only see each other in front of many people.