In 25 years of flying around in helicopters, i've met numerous people (and i'm one of them myself) who have said "and if that had happened in a single we'd have been stuffed".
I've never met anyone who said "If i'd been in a twin we'd have been stuffed".
Will two engines always save you? No.
Are two engines more expensive? Yes.
Does having two engines increase the statistical likelihood of having one of them fail? Yes, of course.
If you have an engine failure in a twin do you have a chance of flying away from it? Yes
If you have an engine failure in a single can you fly away? No