Contrast Derailing Love Interests— where a relationship downgrade happens to a Romantic False Lead so an Official Couple can be hooked up. in a Last Minute Hookup) the two are far from synonymous; a Relationship Upgrade can be the beginning of hardships, trials and tribulations that the relationship may not survive at all.Not to be confused with characters upgrading their abilities by socialization.
Also compare They Do—the point past which the Romance Arc is concluded and the relationship becomes a constant that feeds plot threads.
They lack the confidence, and they don’t trust the process.
Putting trust into the guy that you want to be exclusive with shouldn’t sound like a crazy concept.
The moment when two characters become an Official Couple. In a work, it's that point where until further notice there's no more sense in asking Will They or Won't They? In Real Life, it's that point beyond which you'd feel justified calling the other person "my boyfriend/girlfriend".
There may have been Unresolved Sexual Tension earlier, romantic feelings on either side or even an unmistakable Held Gaze or two, but that was all on paper. This is the kind of plot development that gets an audience's attention, so it is often seen in parts of the plot where it is imperative for the story to do just that (e.g.