Do you think you really know who someone is before you start dating?

Before you start dating, do you think you can know who someone really is after marriage? If a guy had a lot of hidden sins and was very focused on a establishing a hospitable appearence to others... the girl would fal in love with him because of his charm, his skill, his intellect, his wisdom, but once he marries her, she will realize that they are always fighting about how they should conduct their lives, that he now expects her to live by the same standards that he previously held for herself, standards that she is antagonistic and opposed to. Are there any mature married people here who can testify to the fact that they argued with their husband or boyfriend a lot less before the relationship began?