hardwhat am-i

If you throw me out the window, I'll leave a grieving wife. Bring me back, but through the door, You'll see someone giving life. What am I?
Common Wrong Answers
“A letter”
While the riddle indeed involves letters, simply guessing 'a letter' does not specify the correct letter that fits the clues provided.
“A window”
This guess misunderstands the riddle; the focus is on the letter 'n' which transforms the words, not on the window itself.
“A word”
Similar to guessing 'a letter', 'a word' is too vague and does not capture the specific transformation of the words that the riddle describes.