Steps for making Sweet and Sour Pork with Pineapple：Cut the pork tenderloin into small cubes, add sweet potato starch, egg, white pepper, light soy sauce, cooking wine, and a little salt, and mix well to marinate. Adjust the amount of seasonings based on your own cooking experience. In this step, you need to add a lot of sweet potato starch, enough to coat the entire surface of the pork, using the amount of sweet potato starch you would use for frying crispy pork. Cut the green and red bell peppers into chunks about the same size as the pork, dice the pineapple, and mince the ginger and garlic. Put oil in a clean wok, and when the oil feels like it is bubbling, add the marinated pork tenderloin and fry until the surface is slightly golden, then remove. Heat the oil in the wok to a high temperature, add the fried pork tenderloin again, and fry until the surface color deepens, then remove. Put a little oil in the wok over low heat, add ginger, garlic, ketchup, and white vinegar, mix evenly, and cook until it bubbles. Turn to high heat, add sweet potato starch water. Then add the green bell peppers. Add the pineapple, add an appropriate amount of salt and chicken bouillon, and mix evenly. Add the crispy pork, taste it, mainly checking for sweetness, saltiness, and sourness (white sugar, salt, white vinegar). If you feel something is lacking, just add more accordingly.