Create situations where they have to protect each other. For instance, if 707 is in danger because of his hacking activities and MC steps in to save him, or vice versa. This act of self - sacrifice and protection can be a turning point in their relationship. It shows that they care about each other more than just as friends and are willing to put themselves on the line for one another.
You can develop their relationship through shared challenges. For example, if they face a common enemy or a difficult task like decrypting a dangerous code together. This forces them to rely on each other and builds trust.
Their relationship can develop through mutual respect. Gohan respects Android 21's strength and intelligence, while Android 21 respects Gohan's kind heart. This respect can turn into friendship first. For example, they train together, learning from each other's fighting styles. Then, as they spend more time together, they start to notice little things about each other that they like, which gradually leads to a romantic relationship.
To develop their relationship, you can create situations that force them to rely on each other. Say there's a magical storm that endangers Brulee's home. The OC steps in to help her protect it. This creates a sense of indebtedness and closeness. Also, include some tender moments, like the OC bringing Brulee a special treat from their travels. These little things add depth to their relationship.
Their relationship can develop through mutual respect. Naruto respects Yugito's strength as a jinchuriki, and Yugito comes to respect Naruto's determination and growth. For example, in a battle situation, they see how the other fights bravely and this earns them respect for each other.
Their relationship could develop through mutual respect. For example, when Fem Zoro shows her swordsmanship skills in a fight and Sanji sees how brave and capable she is. He starts to respect her more than just as a female crewmate.
Their relationship could develop through shared experiences. For example, if they both participate in a difficult training session together. Naruto's coldness might initially be a barrier, but as they push each other to improve, he starts to warm up to Ino.
Their relationship can develop as Rouge shows empathy towards Shadow's depression. She might start by just being a listening ear. As time passes, Shadow begins to trust her more and opens up. This trust can then turn into a deeper connection, and they may start to rely on each other more.
Another way their relationship could progress is if they are forced to take care of a young or injured Spectrobe together. This shared responsibility would make them rely on each other more, and they would start to notice the little things about each other, like how caring and determined the other is. This would gradually lead to a romantic relationship.
Start with small interactions. Have them exchange glances or brief words during village events. Then gradually build up to them having conversations about their ninja dreams and past experiences. For example, Naruto could share his dream of becoming Hokage and Yugao Uzuki could talk about her time training under certain mentors.
First, start with their initial encounters which are full of conflict since Izuku is a villain and Tsuyu is a hero. As they cross paths more often, they could gradually start to have conversations that make them realize they are not so different. For example, they might both have the same goal of protecting the weak, just with different methods.
To develop their relationship, you could focus on their differences. Trunks is more rational and calculated in his actions, while Broly is more instinct - driven. By having them learn from each other, their relationship can grow. Maybe Trunks helps Broly control his anger by teaching him meditation techniques, and in return, Broly shows Trunks how to tap into raw power. Also, shared experiences like traveling to new places or facing an ancient evil can bring them closer. As they rely on each other more and more, their relationship evolves from mere acquaintances to friends or even something more.