After her husband's death, Rachel comes to England to stay with Philip Ashley, her husband's nephew, who is ten years her junior. Philip succumbs to her charms, but begins to suspect that his uncle's wife may have had a hand in his death.
Here's the trailer from the 1952 version:
(Trailer production has come a long way!)
I'll look into the availability of the older version in case, after reading the book, you can't wait to see a movie version!