"Under no circumstances would it be right for me to go with MGM. Irene shares my opinion"

David O. Selznick is expressing his opinion that it would not be right for him to choose MGM. He is suggesting that he does not agree with the choice to choose MGM which Irene shares his viewpoint. This could imply that he and Irene have discussed the choice and have pertained to the same conclusion that it would not be the best choice. It could likewise imply that Irene knows his viewpoint and agrees with it. In either case, it is clear that David O. Selznick does not think it is the ideal decision to opt for MGM. He is expressing his viewpoint that it would be much better to opt for another alternative.