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]. (DE)
App reference (DE): Book 12, Hadith 38 (DE)
Arabic/English book reference (DE): Book 12, Hadith 1322 (DE)