Answer:
Bruce and Sarah’s union has proven itself useless.
Step-by-step explanation:
Finding the right word or phrase to fill in the blank in the question offers a language challenge for us. Because it is the reflexive form of "it," the word "itself" is a reflexive pronoun. When used as an object referring to the same thing that is the sentence's subject or that was stated before in the sentence, it is especially helpful. When the word "itself" is used in this sentence, it alludes to the union between Bruce and Sarah. It gives the statement the right meaning and can be utilized to finish the gap in the given incomplete sentence.