I don't know of any Arabic or Islamic name that sound similar to that. I found that Sikh people also use this name, and people from many parts of the world. One site says it is from Aborigine origins. It also seems to be a last name in Algeria. And it might be the name of a place in Mauritania.
If Ashmin is from non-Islamic cultures but the meaning is good then you can use it to name a baby.