These words are closely related in meaning but have slightly different applications. Involve means "to contain or include," "to have as an essential feature or necessary consequence," "to absorb," "to complicate": "My work involves a lot of hard work." "This contract involves monthly payments for services rendered." "Do not try to involve me in your problems." Entail shares these meanings of involve but more particularly means "to impose as a burden or problem," and, in legal use,"to limit and direct the succession of property": "Losing weight usually entails controlling one's appetite." "The attorney will so entail the estate that you can inherit nothing."
Dictionary of problem words and expressions. Harry Shaw. 1975.