No, Julia, I assume that we French use "bien" with nothing after, it is a kind of idiomatic expression, although "bien" can be used as a noun or as an adjective as well...
We currently say, talking about someone : "c'est un gars bien" or "c'est un type bien", and also "c'est une fille bien". It is also used with neutral ("c'est bien"
.
About its translation into English, reliable could apply to "une fille bien", I mean it would but as guilon said, being "reliable" may be only one of many qualities for "une fille bien".
I'm sorry, but I really do not see what exactly could match this French text, notably because I'd translate by "good", and it would give something rather weird : "I want to be a good girl" it sounds too reduced and childish, (when it doesn't apply to a female pet -my English friend said that to his doggy a few days ago-)...
I must say these short sentences aren't that easy to translate when there's some specific expression.
What do you say in English, Ian? "great", "nice", "brilliant", what's the word?