I'm pregnant with 4 weeks my husband caught rubella. So I did my rubella tests my IgG is 18.2 (+) and IgM is 0.96 so is that result safe for my baby?

Yes. In general, a + rubella igg means you are immune and the baby is safe. That said, your husband should be extremely careful about maintaining goo hand hygiene and avoiding unnecessary contact until his infection is resolved.