Mara, despite it's lovely sound, is riddled with unfortunate meanings.

In Old Norse, mara means "nightmare, incubus" from the Proto-Indo European *mora- meaning "incubus". As a male name in Sanskrit, मार (Mara), it means "slaying, killing". In the Tupi language of Brazil marã means "war". In Fijian it means "burying place". As a short form of the Slavic Morana, it comes from the Old Slavic morŭ meaning "death, plague". In Hebrew מָרָא (Mara) means "bitter".

There is a Latvian goddess, Māra, who is the personification of nature and embodies the divine aspects of birth, life, and death. She takes a person's body after death while the Dievs take their soul.

The most positive meaning I can find is from the Old English mara meaning "greater, relatively greater, more, stronger, mightier," which in this case is from the Proto-Germanic *maiz.

I was so excited to meet the name Mara as she had never really been on my radar and I wanted to explore it but unfortunately I'm put off by these meanings.