How do you get your 3 almost 4yr old girl to poop in the toilet when she already pees fine but chooses to poop in her pull up diaper help?

Maybe you should go back to the potty just for #2. To start over again with that one so she at least get out of the diaper. Also always make it a positive thing, a party, when she does poop in the toilet or potty. I remember Supernanny used colored balls in a jar every time the child went and the balls represented something like 5balls = a pretty bookmark she got to choose from a box (they are not expensive). The choosing part is the best. In another family they did the poopy-dance waving baloons around and did a little dance and song. Big Hit! When my kids were little we had one of those potty's you put inside the toilet so it wasn't so deep. That can be the next step before or after using the ordinary potty.