The Duke of Cambridge has said he has "struggled at times" with parenthood and he is now more worried about the future.
In a candid interview with Talk Vietnam, a popular English-language chat show on Vietnam's national broadcaster VTV, William said becoming a father had made him more "emotional".
The second-in-line to the throne also hit out at materialism and said he wants Prince George and Princess Charlotte to grow up with "simple aspirations".
He has used his first official visit to the South East Asian country to highlight the damaging effects the illegal trade in wildlife has on some of the world's best-loved animals.
Talk show host Tran Thuy Duong asked the 34-year-old about his personal commitment to protecting wildlife and his family life as well as taking questions from a small studio audience.
Speaking about his children during the 25-minute interview, the Duke said: "There's wonderful highs and wonderful lows. It's been quite a change for me personally.
"I'm very lucky in the support I have from Catherine, she's an amazing mother and a fantastic wife.
"But I've struggled at times. The alteration from being a single independent man to going into marriage and then having children is life-changing.
"I adore my children very much and I've learnt a lot about myself and about family just from having my own children.
"George is a right little rascal sometimes, he keep's me on my toes but he's a sweet boy. And Charlotte, bearing in mind I haven't had a sister so having a daughter is a very different dynamic. So I'm learning about having a daughter, having a girl in the family."
He took a question from a 10-year-old girl about his advice on how an individual could help protect wildlife before going on to describe his hopes that his children would inherit a better world.
William said: "I worry about the future more. When you have something or someone in your life to give the future to I think it focuses the mind more about what you're giving them and are you happy that you've done all you can to leave it in a good state.
"I would like them to grow up with more simple aspirations. I think there's a lot of huge aspirations and people living with an enormous amount of stuff that they don't necessarily need.
"The materialism of the world I find quite tricky sometimes.
"I would like George and Charlotte to grow up being a little bit more simple in their approach and their outlook and just looking after those around them and treating others as they would like to be treated themselves."