In the latest chapter of One Piece this exchange happens between おでん, a skilled swordsman wondering why his disciples won't learn his style and his wife, トキ:
In the English version this was translated as:
Oden: But Oden Two Sword Style is the greatest there is! Why won't they learn it?
Toki: Because they would've fought. A great big fight over who would be your foremost disciple. They love you so much that they would've killed each other.
My confusion comes from the fact that the English translation states that a fight "would've" happened, not that it did happen.
"あなたが好きすぎて死者が出るとこだった" specially seems like something that would imply they did indeed come close to dying after fighting over who'd be the number one disciple.
Based on this context, is it possible that "ケンカになったのよ" is referring to a hypothetical situation?