Tamar should be a girl’s name. There are two Tamars in the Bible—the daughter-in-law of Judah who gets pregnant by him after disguising herself as a prostitute, and a sister of Absalom who is raped by her half-brother Amnon.
Tamaar is a Muslim boy’s name.
See: https://www.urdupoint.com/islamic-names/tamaar-name-meaning-in-english-104106.html