Having a feminine voice isn't just all about pitch. It's also two other things: resonance and melodic intonation.
Resonance is that deep rumbling that you cause when you speak as a male. This happens because all the resonance happens in your chest area. In order to minimize this, you'll have to move the resonance from your chest to your head. A lot of Youtube videos recommend speaking from your male voice and raising the pitch until you feel the rumbling on your chest disappear and even going as far as to speak in falsetto. This is done so that you can learn to control your throat muscles and be able to move the resonance easily. Search for CandiFLA's or karmatic1110's voice videos for some more explanation on this.
Melodic intonation is that "sing-songy" type way that women speak. Men speak in a monotone type manner a lot of the time, but women often vary the way that they speak. This can be learned by observation or watching a lot of shows with women in them
Hope these help!
