"Even this vein of writing is so foreign to me that I am amazed"

David O. Selznick's quote is a reflection on his own writing design. He is expressing his surprise at how various this specific design of composing is from his own. He is impressed at how unknown it is to him, and how it is so various from what he is utilized to. This might be translated as an indication of admiration for the style of writing, as he is in awe of its uniqueness. It might likewise be analyzed as a sign of humility, as he is acknowledging that he is not as experienced in this specific style of writing as he remains in his own. In either case, it is clear that he is impressed by the unfamiliarity of this style of writing.