What is said during a date stays in the date. Relationships are all about trust, so never break your trust by divulging what was said to you on a date. That person trusted to you to open up about themselves, and they had every expectation that you would treat everything as strictly confidential.
What will become of dating if no one can any longer have confidence that what they divulge will be maintained in sacred secrecy? It is absolutely inappropriate to blurt out private information to friends and acquaintances. It could not only hurt the one you are dating, but it has the potential to backfire on you too.