offer one can't refuse

noun2

1. •
   An offer from one side in a transaction with terms so attractive that the other side is almost guaranteed to accept.

   • But in 2001 the government of Singapore made him an offer he couldn't refuse: the directorship of the brand new Genome Institute along with a $25 million starting budget. — 2006
2. •
   A threatening offer by one party for which the results of failing to accept are so unattractive that the other party is almost compelled to accept.

   • The Mafia godfather Rocco . . . makes Jack an offer he can't refuse: marry Carol or else. — 1991