I'd disagree, because just cause it doesn't show them being all loving for more then an hour is because there was something else important that needed to be attended (I.E the pridelands),
Also they originally was going to put a longer love scene for them but changed it for some stupid reason to the current Can you feel the love tonight scene. You can watch the deleted scene either from TLK wiki, YouTube, or here because I posted it yesterday.
But my answer to this statement is no, they love each other, if they didn't Simba would of asked someone else to be his queen whether it's breaking a tradition or not. And in the second movie they still love each other even if they're not the main characters anymore they still love each other very much, no matter how it's not shown on picture, the love is true.
Can't say I've seen very many people say that! I think I recall someone saying something along the lines of that once though - I think they might have been talking about how they didn't like that Simba and Nala were betrothed as kids. Maybe they felt like the couple was forced because of that.
Their romance was portrayed well enough for me, personally. I appreciated that the two were best friends as kids, so they had a platonic friendship which developed into romance when they reunited as adults. I thought that was nicely done. :)
Personally, I'd like to believe that them falling in love was natural and not due to them simply being betrothed. I thought it seemed genuine enough (especially from Simba's point of view, considering he had no intention of returning to his pride when he and Nala first meet as adults).
So I guess I'd disagree with those who say that there is zero chemistry/romance. Although like I said before, I've not really run into much of that either!