Is there a way to date and bang Emma if you have other girlfriends(Bree, Sam, Sasha) I try to ask her out on a date, but she says that she'd never do that to Sam.
To date emma without unnecessary beating around the bush,
You have to let Sam marry Ryan,
Following the wiki you need to stop progressing after Marriage Aint All That,
Instead trigger meeting Emma and progress to and complete the event date,
Then trigger the convo with Emma about Ryan,
After that it's safe to continue with Sam,
If Sam is already your gf and introduces you as such then Emma won't date you,
There's a way around that but it's not something I'd personally want to deal with,
Basically like choosing one or the other.
Check Emmas page on the Wiki for the how to.