I'm a woman, and that statement is not something I relate to at all. Personally, I don't view the "heart" (or at least my own) as anything all that complicated or secret. The secrets, to me, are in some of the "mental files" that contain things I've processed "intellectually" and deemed to go into a "confidential file". If I think about it (considering that I don't tend to refer to "the heart" as anything other than "as in, say, a heart attack" or "as sin, say, the circulatory system" ); I see "heart related" matters (the emotional stuff) as either emotions to be processed or else emotions that have been processed. Then, what remains (as far as "heart-rel;ated stuff" goes, is far from a secret (mainly, I suppose because the bad stuff is processed one way or another and at one time or another; and the good stuff that is left is far too meaningful to even be able to keep secret_.
When it comes down to it, I'm just not a big fan of lumping all women (or all men) into one big category and making statements about what their heart is or isn't.
Having said all that, I've got some overloaded "mental files" that I'd really like to unleash on a few people. Those files, though, have nothing whatsoever to do with "the heart". Believe me.