How solder male fitting of the bathtub water sprout?

first i would not recommend 50/50 solder for it contains lead. this is no longer allowed on potable water systems. locate 95/5 or 60/40 solder, soldering flux,emory cloth or sandpaper and a map gas or propane torch. first clean the copper pipes end to where the fitting will be soldered, clean the inside of the male adapter. apply a generous amount of solder flux to both male fitting and copper pipe. heat the fitting and not the pipe, apply solder and when the fitting sucks in the solder, you should have a good penetration. check around the fitting and you should see a bright shiny ring around the fitting with no pits or gaps. this is basically soldering 101, best of luck .