The book of Ruth is one of many books in NK that barely makes it in terms of Torah compliance.
Story does make sense, however I do have one question: Was Ruth, great-grandmother of David a virgin when Chilion took her? If you remember, we are prohibited to intermarry with Moabites
(Deuteronomy 23:3-6). The only Moabites that Hebrews could marry were the Moabites virgins (Numbers 31:18)
But the Book of Ruth does not say a word about Ruth's virginity as, say, Torah does in Genesis 24:16, so it is possible to assume that she was not. This would make the King David illegitimate according to the Laws of the Torah.
So as you can see, books of NK have many flaws and inconsistencies in the narrative, that explicitly contradict the Written Torah. So be aware of this.