Michelle, I do understand where you are coming from with the spontaneity you can get with hand holding a camera for portraits.
The thing is that Laostyle17 has little to no experience with portraiture and is asking for advice. I just feel a tripod will slow things down so he can concentrate on the shot.
Also we don't know what camera he is using. If he's got a Mamiya RZ67 like I used to have it can be a bit awkward for hand holding!