Make no bones about something

For centuries, bones have been a problem in food, especially fish bones. Thus, from at least the 15th century, and probably before that, bones came to be synonymous with problems or difficulties. Make no bones about something means to have no problem in stating one's opinion about something, however unpleasant or distasteful it may be. 'No bones about it' means there is no problem or question about the certainty or veracity of something that is under discussion. All these expressions have been in use since at least the 1500s. See also Bone to pick and Bone of contention.