"The woman eats an onion."
Translation:La mujer come una cebolla.
Because it is saying she eat AN ONION not just onion She eats onion vs She eats an onion.
Kind of but no. That's akin to saying something like, “The woman she herself eats an onion." You could say, “Se come una cebolla." That's more like, “One eats an onion." or “An onion is eaten." It is more distant or impersonal, but acceptable in certain situations. However, the translation of “The woman eats an onion" is only properly (literally saying the exact same thing) translated as the lesson says.
People do sometimes speak like that, but it is like saying, “He himself likes to swim." Himself is unnecessary. Who else is he but himself? You will find that form at times, but it is not exactly the question being asked here.
What is the meaning/purpose of ‘se’ in the ‘correct translation’ - La muter se come una cebolla.?