It was not difficult for Dian to find Egi's whereabouts. City P was only a small town that was very easy for Dian to reach. Being Bara's secretary and assistant required Dian to be able to do everything. Dian should be able to take care of Bara's work or personal affairs.
Dian had many friends and connections. Finding Egi was not impossible for her. Dian's mission this time was to secure Egi. Didn't let Egi mess up Bara's wedding reception. If that happened, Ranti, Bara's mother will be faster to meet God. Ranti had a heart disease and can't take bad news.
Bara didn't want to lose Ranti because of what he did. Bara wanted to show a good image in front of his parents.
Nobody knew a single thing about Bara. It was Dian who knew everything in detail, including the love affair between Bara and Egi. They have been in a relationship for five years. Dian was often used as a shield to cover up the forbidden relationship between Bara and Egi.