One possible scenario could be that in the fanfiction, Natsu finally realizes his deep feelings for Lucy and decides to be honest about his love. It might be a moment of great emotional intensity, perhaps after they've been through many adventures together.
It's possible that the fanfiction is set in a particular arc where the danger they face makes Natsu realize he doesn't want to lose Lucy. His declaration of love could be a way to give her strength or to make sure she knows how important she is to him. This could also affect their interactions with other characters in the fanfiction, like their friends might support their new relationship or there could be some jealousy from other characters.
Maybe in the fanfiction, there has been a build - up of tension between Natsu and Lucy for a long time. Natsu's declaration of love could be the climax of the story. It could also lead to a new chapter in their relationship, where they start to explore their feelings more deeply and face new challenges as a couple.
One possible scenario could be that Vegeta finally realizes his deep feelings for Bulma during a moment of great danger. He might see her in harm's way and his protective instincts kick in, leading him to blurt out his love.
Their relationship might become more affectionate. They could start holding hands, hugging more often, and generally showing more physical closeness.
One possible scenario could be a really emotional moment where Castle finally gathers the courage to express his deep feelings for Beckett through his fanfiction. Maybe he uses the stories he writes as a way to convey his love in a more creative and less intimidating way.
One possible plotline is that Natsu starts writing in the diary about his confusion regarding his feelings for Lucy. He might write about how he gets jealous when other guys show interest in her. Another plot could be that Lucy accidentally discovers the diary and confronts Natsu about it, which then leads to them finally admitting their feelings for each other.
She might be overjoyed and immediately reciprocate his feelings. In many fanfictions, their relationship is built on a deep connection, so this could be a natural response.
The theme of sacrifice also appears. Natsu might be willing to sacrifice his own well - being or goals for Lucy once he realizes his love. For instance, he could give up a dangerous but lucrative mission to stay and protect her. It's all about showing the depth of his new - found love.
Maybe he is genuinely interested in the creativity and the unique world she has created in her fanfiction. It could also be that through her fanfiction, he gets to know a different side of her, a more imaginative and expressive side, which he finds very appealing.
Perhaps they met at a summer camp during their childhood. Natsu was always the adventurous one, leading Lucy on little explorations. They could have made a pact under a big oak tree there to always be friends, which gradually turned into something more as they grew up. They might have shared their first kiss by that tree as teenagers, as a natural progression of their deepening feelings.
Well, in some fanfictions, it could be through a dangerous situation. Maybe Lucy is in peril and Natsu's intense fear of losing her makes him realize his love. For example, if she's captured by a powerful enemy, Natsu's desperation to save her and the way his heart races at the thought of her being hurt could be the trigger.
The theme of unrequited love can also be common in some 'lucy loves natsu fanfiction'. Maybe at the start, Natsu doesn't realize Lucy's feelings or is too focused on other things like his next adventure or his training. This creates a lot of tension and drama in the story, as Lucy tries to hide or express her feelings while Natsu is oblivious.