It could start with mutual respect. Goku respects Female Vegeta's strength, and she respects his. Then, they might have some friendly competitions which gradually lead to a closer connection. For example, they could compete in a tournament and after the fight, instead of being enemies, they start to understand each other better.
It could develop in a rather comical way at first. Goku's simple - mindedness might annoy Female Vegeta who is used to a more formal and proud Saiyan environment. But then, when Goku shows his incredible power and determination in battle, Female Vegeta would be intrigued. As they interact more, she might start to understand his way of thinking and they could form a bond. For example, during a long and tough battle against a strong foe, Goku's positive attitude might inspire Female Vegeta to fight harder, and that could be the start of a deeper connection.
At first, they might still be competitive. But as they face the challenges of the different time periods together, they could start to respect each other more deeply. For example, if they are in a time when they are much weaker, they would have to rely on each other's skills more.
The relationship could develop from a simple rivalry. They constantly compete to be the stronger one. However, in a particular fanfiction, during a life - threatening situation, they have to rely on each other completely. This makes them realize that there's more to their relationship than just competition. Female Goku might show concern for Vegeta in a way that surprises him, and he starts to have feelings for her. And from there, their relationship evolves as they explore these new emotions.
At first, Female Vegeta would probably be dismissive of Goku. She's proud like Vegeta in the original series. However, Goku's pure heart and determination could gradually wear her down. They'd start training together, and during these training sessions, they'd share their fighting philosophies. This exchange of ideas would be the foundation for a deeper connection. As they face tougher opponents and Goku saves her life or vice versa, their bond would strengthen and evolve.
It often starts with a shock or surprise at the mpreg situation. Then, they gradually learn to rely on each other more. For example, Vegeta might start to show a more caring side that he usually hides, and Goku might become more responsible. They'll have to communicate more, sharing their fears and hopes about the future with the baby.
At first, Female Beerus may see Goku as just another mortal. However, as Goku shows his extraordinary power and determination, she begins to view him in a different light. Maybe she starts to trust Goku more and more. They could share stories about their past battles and experiences. This sharing could lead to a deeper bond between them, evolving from a simple acquaintance to a true friendship over time.
It could develop through mutual admiration for each other's power. Goku is always looking for strong opponents to test himself against, and Female Frieza is no slouch in the power department. As they spar and train together, they might begin to respect each other more. This could lead to a friendship where they exchange fighting techniques and stories of their battles. Over time, this friendship could deepen into a more meaningful relationship where they trust each other completely.
Their relationship could develop in a very interesting way. Given Naruto's background of being an outcast in his village at first, he might be a bit hesitant to fully embrace Goku as a brother. But Goku's open - heartedness would gradually break down those barriers. Goku would introduce Naruto to his friends in the Dragon Ball world, and Naruto would do the same in the ninja world. They would start to share their stories, like Naruto's fight against Pain and Goku's battles against Frieza. Through these shared experiences, they would grow closer and closer, until they are inseparable brothers who are ready to take on any threat to their combined worlds.
Their relationship might start with distrust. Goku would be wary of a being related to Cell. But if the female Cell shows good intentions, Goku could gradually accept her. Eventually, they could become friends or even more.
In a fanfiction, their relationship could develop as Goku becomes more aware of Chichi's needs. He might start to be more present at home, not just for training. For example, he could help Chichi with household chores in his own clumsy way, which would show his growth as a husband.