Arrows Of Desire by Emma Blair
When Steve is killed during enemy action, Beth is devastated. They were due to elope to Gretna Green the following week, and their happiness was complete with the news of Beth's pregnancy. But now, alone and unmarried and with a baby on the way, Beth must survive by herself in war-torn Glasgow. When Beth meets handsome Canadian Gene, a friendship begins; for the first time since Steve's death Beth finds happiness. When Gene asks her to marry him and live with him on his farm in Canada, Beth seizes the opportunity of a better life for her and her child.
But it doesn't take Beth long to realise that Gene hasn't told her the whole truth and that the farm doesn't belong to just him - his sister Loretta lives there, too. And Loretta makes it very clear that Beth isn't welcome and that she will stop at nothing to get rid of her - even if it comes to murder.