The relationship could develop through a magical object. Let's say there is a charmed mirror that shows glimpses of the past. Harry accidentally activates it and sees Ariana. He becomes obsessed with finding out more about her. He then uses his skills and the help of his friends to research about her. As he uncovers more about her life and the hardships she faced, he feels a deep sense of empathy and a connection forms. He might even start to see her as a sort of kindred spirit, as they both have had difficult experiences in their lives.
Perhaps Harry discovers a hidden room in Hogwarts that was Ariana's. As he explores it, he starts to feel a strange bond with her. He then uses magic to try and bring out her memories or essence. As he gets to know more about her, he starts to see her as a friend and someone he wants to protect, much like he does with his own friends.
She is often portrayed as a tragic figure. Writers usually emphasize her delicate state, both physically and mentally. Her magic is also a key aspect in many portrayals, with it being either a source of her pain or a hidden power waiting to be unleashed.
Another way is through Quidditch. Suppose Padma is a big Quidditch fan and Harry is still involved with the sport in some way, like coaching the Gryffindor team. Padma comes to watch a match and after the game, they talk about strategies and the love for the sport. This common ground can gradually build their relationship.
In fanfiction, their relationship might develop through shared adventures. Imagine they have to find a lost magical artifact that has the power to destroy both their worlds if it falls into the wrong hands. As they travel across different dimensions and face numerous obstacles, their bond strengthens. Harry's determination and Kitty's resourcefulness complement each other, and this could be the foundation for their romance.
In fanfiction, their relationship might begin with a chance encounter in the Hogwarts library. Hannah is looking for a book on herbology and Harry helps her find it. This simple act of kindness starts a conversation that grows over time. As they get to know each other better, they find that they both have a love for Hogwarts and a desire to protect it. They could then face various challenges together, like dealing with a group of Slytherins who are causing trouble. Through these experiences, their relationship deepens, from acquaintance to friend to something more romantic perhaps.
It can start with simple acts of kindness. For example, Harry could save Gabrielle from a minor accident during a wizarding event. This would make Gabrielle look up to Harry, and from there, they could start having conversations and getting to know each other better.
It could start with Harry being forced to work with Umbridge on a special project at Hogwarts. At first, they're at odds, but as they work together, they gradually find common ground. For example, they might both be interested in a particular area of magic that is relevant to the project.
The relationship could start with mutual distrust. Harry has been taught certain things about goblins, and they have their own reservations about wizards. But as they are forced to work together on a task, like protecting a powerful magical artifact from dark wizards, they begin to see each other's strengths. Harry realizes the goblins' knowledge of magic items is invaluable, and the goblins see Harry's courage and loyalty.
The fanfiction might show a more adversarial relationship. Harry could start to oppose Dumbledore's plans instead of following them blindly. This is very different from the original where Harry was mostly compliant. For example, in the original, Harry accepted Dumbledore's tasks like finding the Horcruxes, but in the fanfiction, he might question the motives behind these tasks and resist them.
The relationship would become very strained. Harry's rejection would likely make Dumbledore re - evaluate his actions and how he has interacted with Harry. Dumbledore might be shocked at first, since he probably thought Harry was on the same page as him most of the time.
As the story progresses, Dumbledore might try to make amends. He could start revealing some of his secrets to Harry in an attempt to regain his trust. Harry, on the other hand, would be hesitant at first but gradually start to listen and understand Dumbledore's reasons.