Why does Chubukov think it is a burden to be a father of a grown up girl?
Bcz Natalya was fighting with Lomov for petty matters as she didn't know tat Lomov had come to propose her. Again after knowing also she fights. When Chubukov solves the problem and says to Lomov that Natalya accepts your proposal. It was a very tough time for Chubukov to convince Natalya. So he says that it is difficult to be a father of a grownup girl.