Just tell the truth and stop beating around the bush.
Tips
usage
实话实说 is more emphatic than 说实话. It often implies a demand for honesty or a declaration that one is being completely candid. Can be used as a verb phrase (你就实话实说) or as a sentence opener.
culture
实话实说 was also the name of a famous CCTV talk show (1996 - 2009) hosted by 崔永元, known for its candid style.