most garden hose is 5/8ths (at least the cheap ones are), never seen a female version of that, only the mail version, you may have to get a short length of garden hose and put a couple of female fix its on it to get the desired effect.
the other way to get er done is to get a 3/4 slip by slip union and a 3/4 x 1/2 thread bushing, glue the bushing into one end of the union and glue the union to the pipe, then you can put a standard brass hose bib with a 1/2 mail end going toward the water and be able to turn it off to boot.