Anas (May Allah be pleased with him) reported:
The Messenger of Allah ﷺ said, "He who supplicates sincerely for martyrdom, it will be granted to him even though he is not killed on the battlefield."

[Muslim].

وعن أنس رضي الله عنه قال: قال رسول الله ﷺ: "من طلب الشهادة صادقًا أعطيها ولو لم تصبه" ((رواه مسلم)).