A Sweet & Clean Western by USA Today & Wall Street Journal bestselling author Sierra Rose. 

When Nathaniel Burton, notorious gambler, is murdered in the middle of a poker game, it leaves his three daughters and niece not only bereft but destitute. None of the young women have been educated to support themselves; and, with their luxurious lifestyle suddenly torn away, they are desperate to gain some sort of financial security before they end up in the street.
Camellia, as eldest and most responsible, explores various options but can find nothing suitable. Until she comes across the Mail Order Brides section in her local newspaper. She applies to marry one Ben Forrester, he accepts, and the deed is done.
Within a few months, the Burtons have left behind their St. Louis mansion to the bank's foreclosure, hired a wagon train and drivers, and set off for a place in northeast Texas called Turnabout. There, Camellia discovers that her intended is kept quite busy, running a mercantile store and serving as mayor. 
So many adjustments must be made. Transferring from large bustling city to small compact town. Moving from sumptuous living to Spartan surroundings. Transforming from blushing maidenhood to blushing wifehood. 
And engaging in arguments.
Ben and Camellia have been married one whole day when a rousing quarrel flares up out of nowhere. He is obstinate; she is opinionated. Inevitably, the two clash, and Ben leaves on a business trip before the matter can be resolved.
After an unprovoked and unforeseen attack by outside forces, survival itself is left in question. Both realize they need to re-think their values, and decide what is most important in life.