see give away, def. 3.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
How to use give oneself away in a sentence
He had given himself away to Stella as he had never in his wildest dreams supposed that one could give oneself away to a woman.The Second Fiddle | Phyllis Bottome
One has to be so frightfully careful not to give oneself away when one knows everything.A Young Girl's Diary | An Anonymous Young Girl
One must strive with one's whole strength to give oneself away.The Light Shines in Darkness | Leo Tolstoy