Princess Tilde is the crown princess of Sweden and the wife of Gary "Eggsy" Unwin.
Kingsman: The Secret Service
Crown Princess Tilde of Sweden was one of several heads of state and VIPs who met with billionaire and philanthropist Richmond Valentine to discuss about global warming. She and Prime Minister Morten Lindström met with Valentine over dinner, where he proposed his ideas. While the Prime Minister was willing to side with him, the princess thought him to be completely insane, and Valentine locked her away in his base in the mountains.
Later, she would be discovered by Eggsy, who was going back through the base to find and kill Valentine. He asked if he'd get a kiss if he freed her, since he never kissed a princess before, to which she said that she'd give him "more than a kiss" and that he can do it in the asshole. The last thing we see of her is her backside on Merlin's screen, at which point he closes his computer.
Kingsman: The Golden Circle
Tilde is first seen in Eggsy's new home, acquired from Harry Hart, talking to some of his street friends about the dinner that was arranged by Tilde's parents, the King and Queen of Sweden. Later in the film, Tilde is seen and heard on the phone with Eggsy while he is at Glastonbury on a mission for Statesman. She's made upset at the thought of Eggsy having sex with another woman despite his explanation and attempts to coax a marriage proposal from him as an ultimatum for her permission. When Eggsy reacts poorly and requests that they discuss this further at a later point, she rejects Eggsy's following calls and ignores his texts.
Tilde is later seen to have acquired the blue rash due to smoking tainted weed distributed by Poppy, and reaches phases 2 and 3 of the disease. After the Kingsman have completed their mission, her parents administer her the antidote, allowing Tilde to heal almost instantly and return to normal health.
The last scene features the wedding of Tilde and Eggsy, in the presence of their families, friends and colleagues.