What you are talking about in the married scene is the emotional context of the way she said "you". I guess in the movie she probably said "anata"? But this i

What you are talking about in the married scene is the emotional context of the way she said "you". I guess in the movie she probably said "anata"? But this is not a very good example, as regardless of emotional context, simply using the word "anata" instead of his name is a solid contextual message that they are married. Otherwise she would say his name, or his "role" (father, older- brother, younger-brother, etc). I'm sure there are some sentences that require clarification, but this is true in english as well. But generally speaking, it is not an issue. Only very rarely do japanese people end up needing to disambiguate through pantomiming the strokes of kanji in the air or saying "you know, the first character from such and such, not the character from that other word" (except when discussing the writing of names, which is totally insane and is the real life version of the old monty python Throatwarbler Mangrove sketch).