2. Question: For allowing a woman to get remarried why is a person reliable even if he only saw the dead guy by the light of a candle or the moon at night but if a non-Jew or Jew would say that they saw a dead guy at night by the light of the candle or moon and he was just speaking masiach lifi tumo he is not believed?
Background:
A. The Shulchan Aruch (Even HaEzer 17:22) says that when you look at the body to recognize it in order to testify about it, one can even check and see it at night by the light if a candle or the light if the moon.
B. The Pischei Teshuva (91) is in fact in doubt whether a person who while just telling over a story happens to have mentioned (unintentionally), mesiach lifi tumo, happens to say he saw a man killed or dead when he was walking at night, by the light of a candle or the light if the moon.
Answer: If a person is testifying he is trusted to be sure to get a good look at the body. But if he is just telling a story, even though masiach lifi tumo is normally believed but because of the circumstances it was dark maybe he didn’t pay close enough attention and he saw wrong.