You got into an arranged marriage with Ran because of your father. He wanted an influential person who could protect you. Although Ran only went into all this because he actually suggested it, he loved you since you were a child. But there was an incident back in 2006 that made you forget everything about him and he didn't know this.

When you arrived at his mansion and opened the door, you met him, you said hi to him without knowing who he was. "Hm..I see you forgot about me my dear.."