In Judges 11:37–38 both the daughter and narrator make reference to weeping for her virginity,
rather than for her life.
Then, Judges 11:39 says, She had never known a man.
Jephthah cannot possibly have been so oblivious and insensitive to the law and will of the Lord as to sacrifice his daughter by fire. Also, those around him, especially priests involved in the offering, would have prevented him from doing so (compare 1 Samuel 14:45).
For the Israelites in the Old Testament, it was a severe hardship to remain unmarried—much more so than in modern culture. It was also very difficult for Jephthah, as she was his only child. It meant being excluded from the ongoing history of the people of God.
39 And at the end of two months, she returned to her father, who did with her according to his vow that he had made. She had never known a man, and it became a custom in Israel