Though I have watched Guys and Dolls dozens of times, it just clicked that Marlon Brando and Jean Simmons were not good singers. However, I do not think it matters. I believe I previously wrote I felt they had some of the best chemistry I have ever seen, and I still hold that opinion. While many probably do not remember Marlon and Jean as a great, legendary screen couple (they only made two films together), they probably could have been, and I consider them that anyway. I watch this musical again and again because their relationship seems so authentic to me. This cancels out any lack of ability the film may show.
Not to mention, in this scene, both actors do little, special things. For instance, it kills me every time Marlon offers her that flower in the can. Although, he often does quirky improvisations like that in his films.
Are there any actors you like watching together?