After one screwball comedienne, Thelma Todd, we now have another, Carole Lombard. There are certainly Lombard secretarials about, particularly in the smaller formats (7"x5" and postcards), but I haven't managed to locate a signature study showing such secretarials.
I think this is a genuine Carole based on the PSA and RR Auction examples I've looked at and the fact that this is a high quality, double weight, canvas-backed 10"x8", stamped to the reverse by the well-known Hollywood photographer Elmer Fryer. Interestingly, there is also a stamp for the magazine Cine Mundial but the dedication is to a different publication, whose name I cannot read.
This was one of the first "Latin American magazine portraits" I ever bought by the way: