Lidewij Vliegenthart is Peter Van Houten’s assistant, and a genuinely kind, altruistic person. She warmly welcomes Hazel and Augustus to Amsterdam and makes sure their experience is as rewarding as possible. She is also clever, strong-willed, and brave. She fabricates a narrative to get Peter to meet Hazel and Augustus so that he can “see how [his] work matters,” and so that Hazel can meet her hero. She arranges everything and forces Peter to talk to them when he tries to send them away. Lidewij is evidently motivated by a desire to do good and is unafraid to take initiative. She refuses to tolerate bullies and scolds Peter for his cruelty towards Hazel and Augustus. She then resigns, indicating her willingness to sacrifice her job for her morals and integrity.
Despite being newly unemployed, Lidewij selflessly prioritizes Hazel and Augustus and takes them to the Anne Frank house so that they can still make the most of their trip. There, Lidewij tries to make them feel as comfortable as possible; she helps Hazel up the stairs and asks the other tourists to be patient as Hazel slowly makes her way to the top. Lidewij's nurturing and supportive presence demonstrates her compassion and kindness. She does not want Hazel and Augustus's experience to be any less meaningful than that of any other tourist visiting Amsterdam. Her generosity at every turn is indicative of her strong moral character, particularly at the end when it is she who finds the notebook pages containing Augustus’s final message and passes them on to Hazel. Lidewij is not just a means of facilitating contact between Hazel, Augustus, and Van Houten; she serves as a voice of reason for Van Houten, and her continued compassion offers a stark contrast to Van Houten’s brutal nihilism.