Would it be considered ẓihār if a husband said to his wife, "We will go into the room and be like siblings," and then had intercourse with her?

A man likening his wife to his sister by saying, "You are like my sister," or calling her "O my sister," is not explicit ẓihār, nor does the ruling of ẓihār apply to it unless he intended it, because the wording is not explicit. If he did not intend ẓihār, then ẓihār does not occur.