Their relationship could develop through mutual respect. Luffy respects Whitebeard as a powerful and respected pirate, and Whitebeard respects Luffy's determination and potential. For example, they could start with a simple exchange of stories about their adventures at sea.
A 'whitebeard x oc fanfiction' often involves creating a unique story with an original character (OC) in a relationship with Whitebeard. It can explore different aspects like their adventures together, how the OC might change the course of events in Whitebeard's world, or simply their emotional bond. For example, the OC could be a new crew member on Whitebeard's ship, bringing in fresh ideas and challenges.
Whitebeard's speech is definitely fictionally significant. It can reveal his character, motivations, and influence the plot in meaningful ways. It might also stir emotions among the characters and the audience.