Dear Friend
It is an expensive place to live. If your friend is going there for work, she must be knowing that, life is expensive here in Singapore. You have to pay allot of taxes. But matter of the fact is, it is a very nice place to live. Clean and secure environment. It seems like I am in a Europe. If she is coming for studies, it is the best place, full of specialized and accredited universities etc. If she is coming as tourist, it is a place worth visiting.
Majority of the population is Chinese, and the remaining are Indians and some Goras. Rules and regulations here are strict. Thais why you don't need to worry if you are a female or an alien. You are safe here. People are good and co operative.