You tell her that you will take her away from her current home, she'll be free from Giron and Yasmine or even Dave who apparently gives her some stares atleast.
She doesn't want to face that new world alone though, so she asks for your companionship.
She isn't askeing for a public relationship but atleast a mental one, I think she is fine to give sex for such a relationship as she is far more open to the MCs advances than most of the girls.
It's more like these people choose to act differently than the way they were raised.
They didn't question which way they should go based on social norm.
Parents are supposed to teach children the social norm, but it's up to them to decide wether or not they agree to them... askeing what the social norm is would be considered a failure in raising a child.
That's entirely up to you... each choice has a meaning in the game as they progress down a road, it's not a question about what is best, but what you want to achieve and how you consider yourself enjoying the road chosen the most.
You will reach an end on each route, the path you take and the Events you can see and enjoy are something that you have to decide on, and the game is very clear about what branching pathes will entail.