We sometimes say "Noapte bună, vise plăcute." You can use "vise plăcute" ("pleasant dreams") then, it's common and nice.
Of course, there's also "Noapte bună, vise plăcute/puricii să te sărute," our version of "Good night, sleep tight, don't let the bed bugs bite"
It literally means "Good night and pleasant dreams, may fleas kiss you." I can't say for sure that she'd like you to say that
I'm so sorry, Mike. I just realised I should have written "Somn uşor" instead of "Noapte bună" in that little poem. It means the same, but that's the way we usually say it (something to do with the rhythm).
It's OK and don't worry about making mistakes with my translations because my friend knows I haven't been learning Romanian for a long time and just the fact I'm trying is enough [at least I hope it is].So thank you for the correction and just in time, I was intending to write this message tonight.
Mulţumesc foarte mult Trisia.