Transcript for Maria Teresa, the grand duchess of Luxembourg, on being a Latina married into royalty
Reporter: Once upon a time in a small European country just an ocean away, there was a beautiful castle. People, they love to come here. It's a nice atmosphere. Reporter: And look at this view. Yes, it is. It is very, very impressive. Reporter: Inside that beautiful castle lives her royal highness Maria Teresa, the grand duchess of Luxembourg. The equivalent of the country's queen. This is your wedding day? That's our wedding day. Reporter: In a rare interview, the grand duchess is pulling back the curtain on what life is like in modern-day royalty. It's a life of giving up your liberty. It's a life of commitment to your country and especially of service. Reporter: It's a storybook tale with an unlikely character. It's hard not to think of this love story as a little bit of a fairytale. It is, it is. It does have a lot of fairytale in it. Reporter: The grand duchess haling from Cuba, who fled to New York in the middle of a revolution. Her story in some ways so similar to Meghan Markle's. Two women, two outsiders, trying to find their place within an exclusive society they never imagined being a part of. What advice would you give to someone who is an outsider? It is a life that demands more. And when you're confronted to situations where you cannot do what you would want to do, well, you're not going to denounce the whole system that you belong to. You're lucky to have married into this incredible family situation. Reporter: For the grand duchess, her life now could not be any more different from the one she grew up with. I was born in Cuba. It's very special, belonging to a Cuban family. It's joyful, it's happy, it's full of -- it's Latin, it's full of life. And it's -- it is the root of who I am. Reporter: When she was just 3, her family fled during the revolution, finding refuge in New York City. After New York, she was studying in Geneva when she met her prince charming, Henry, the grand duke of Luxembourg. So here we are, beginning of university, and I meet this young boy. And I do know that I said to myself -- we're going to keep a distance. Worst thing you can do is fall in love with a crown prince, what a problem. That was my thought. You were one of the first outsiders to marry into a royal family anywhere. You're also not from a European background, you're Cuban. What was that like for you? At the time, it was not usual for a young girl who was not of the royal circle to marry into the royal circle. It had to be incredibly difficult. Here you are, a young woman falling 92 love, the love of your life, not knowing whether or not you'll be able to actually spend your lives Yeah, it was hard. And the more the years passed, the more stressful it became. Could you have ever dreamed thrive would bring you here, grand duchess of Luxembourg, a royal family in Europe? Really not. No, no, no. I would have people working for us in the household that would come and address me and say, your royal highness. Once or twice I did look in back of me to see who they would talking to. What my mother told me before I married, and I always kept that very chose to my heart. She said to me, don't ever change. Reporter: As the grand duchess discovered, when you marry into royalty, you marry into centuries of royal tradition. 44 countries have monarchies, from the himalayan kingdom of Bhutan and the streets of Tokyo to the shores of Tonga and the palaces of the uk and Europe, kings and queens wielding power that's intangible but When you enter a royal family, when you realize is that you marry not only the crown prince, as I married, but you also marry the institution. And you marry the country. Reporter: Critics argue the monarchies of today are undemocratic, cost the taxpayers money, and are increasingly outdated. Perhaps the most famous of the Royals, the duke and duchess of Sussex, the flaws of mind monarchy have been deeply felt. Meghan Markle joinin Oprah Winfrey open -- It's easy to have an image that's far from reality. That's what's tricky the past few years, when the perception and reality are two different thins and you're being judged on the perception, but you're living the reality of it. What was your reaction when you heard that prince Harry and Meghan were going to be stepping down as senior Royals and moving to America, leaving the united Well, of course it's sad. But I wouldn't want to -- to place a judgment now. I think that it is a tremendous challenge to enter a royal family. And it a tremendous honor. And an incredible responsibility toward that family that accepts you with open arms. Reporter: For thetry years that she's lived and served in her adopted country, the grand duchess has never forgotten her roots. How much does your background play into the way you are today? I have the spontaneity of the Cubans. But I also have learned through living in the states, in Switzerland, now in Luxembourg, that you have to take time to reflect. That's where I say that all cultures have brought me a lot. Reporter: Her multicultural background and experience directly impacting the causes she chooses to champion, including leading a groundbreaking conference supporting women who have been raped during war through her organization "Stand, speak, rise up." I can face these causes because I feel so much for the people who are suffering. From these problems. I'm living in the most privileged way. I have to help those who really are living the worst situations. Reporter: The grand duchess says she will continue to honor and serve the monarchy and country that has taken her in as their own, and in doing so hopes to represent the best of what a royal family can be. The thing is this. In a monarchy, the people identify themselves to a family. And it's a family that is above politics. You are there, you are the you are there for all. And you are always at the service of all and open to all. Reporter: For "Nightline," I'm Maggie Rulli in Luxembourg.
This transcript has been automatically generated and may not be 100% accurate.