"Is it because of the depth of field?"
It's definitely one of the issues, as only tiny parts of some petals are in focus, almost nothing. And even those smal areas are not particularly sharp.
There is also quite a bit of noise and the image too dark.
As regularly mentioned here, keep in mind that there are many millions of pictures on Adobe Stock and it's therefore very difficult to get sales, even of those of excellent quality.
Hope that helps,
Michael Niessen - Photographer, photo-editor, educator
ich werde bei weiteren Einreichungen mehr auf die "dof" achten.