Looking for YoungAdult/Romance/Fantasy series of (at least) four books, similar to the "Selection"-series - but with vampires. USA is ruled by a royal family rumored to be vampires. For most normal human people, poverty and starvation is a problem. A resistance movement is active.
When a competition is announced to help the Crown Prince find a bride, the mother of our heroine convinces her to apply. She has a kid sister - and maybe a kid brother, and an older brother in the resistance. She gets picked as representative for her district, along with another girl from the poorer side of town. This girl is disresepectful to the Queen, is attacked, and turned into a vampire.
The girls each gets servants and gets dressed up, and goes on arranged dates with the Prince. The girls are interviewed and profiled, and together with clips from their week and their dates, a TV-show is aired every week. Some girls are sent home. Our heroine and the prince hits it off. When her sister gets ill, the prince joins her on a trip home and arranges for a doctor.