Help getting my female character to open up to my male character?

So, I’m writing a book, and I need some help with how to get the two main characters to fall in love. Here’s the basic plot, the specific question is below that.

The protagonist, Blaise, has to go to a different region/part of the Roman Empire to manage a scrap of land in that area he recently inherited. He winds up falling in love with Vita, one of his neighbor's slave girls who’s basically a sex slave—the main thing is that she doesn’t trust men.

*I know the plot seems a little cliche, I asked a question about this here on answers before. I have a twist planned for later.

It’s the Vita learning to trust men again bit that I’m having trouble with. I need ideas for a scenario that can help her warm up to Blaise. He’s curious about her from the get-go, even if he doesn’t realize exactly what she does for a living.

Initially, Vita was curious and trusting, but that’s part of what got her into “trouble.”

But after years of rough treatment and being held against her will, and having a baby she lost, she’s retreated into a kind of a shell of a person. What I want to happen is Vita will slowly open up to Blaise, and part of her original personality will open up…but the problem is, I can’t think of anything that would happen to get her to trust him in the teeniest fraction. My original idea was that he stops her from getting whipped in the halls when he’s visiting, but that strikes me as both unrealistic to the culture and time and a little…obvious.

Blaise’s personality – he’s intelligent, a bit sarcastic, has a low self-esteem but is too proud to admit it, but he wants for things to be fair and he’s really loyal.

Any ideas are appreciated! Thanks so much.