To the OP:
Based on your description I'd say this girl is a mistyped ENTx of some sort. Blunt communication and promiscuity are not out of character for ENTx's at all. It is also not uncommon for an ENTx to mistype as INTP. The other option is that she really is an INTP, but her upbringing taught her to extravert behavior to the point so that she acts like a ENTx much of the time. That's my $.02.