The relation between Ange and Juza is more elaborate in the game and in the manga, because the anime treats just the first 4 Episodes of the Visual Novel. 26 episodes of an anime aren't sufficient to describe well all the characters and their relations, they're too rich of facets.
Ange makes her first apparition at the end of Episode 3: Banquet of the Golden Witch, that in the anime coincides with 18th episode. Just 9 episodes for her, so they're not much for the development of the relation with Juza. Many things are changed and a lot are deleted.
Juza is her body-guard and the only one closes to Ange. He takes care of her since the tragedy of Rokkenjima, and this is the reason why she considers him like a big-brother. He has feelings for her and it's the same in Ange's reguards, but nothing is clear.
We met them together for the first time in 19th episode of the anime. The scene of Juza's introduction isn't warm as the game recounts.
This is the original scene (takes from the manga, that REALLY is more complete and intense of the anime), when she jumps over a window in order to escape from the guards of her aunt Kasumi, and after an hard landing above the roof of a car, he'll get her in his arms.
This image is famous in the net, and I love it too much too (so I use a fan-art of it to making the graphic of this site, eh)!
Because when Ange is jumping, she thinks:
"But unfortunately, the princess on the top of the tower won't just wait for her prince to come to rescue her."
The last, famous words! XD
Juza saves Ange taking away her from the stalkers, and when she sits beside him, she thinks:
" Don't you tell me this is my prince"
It seems a sign of destiny, isn't it? Juza was fired by Eva but Okonogi asked to him to take Ange in a journey, and since the pay was good and he know her well, he accepted.
Ange isn't enthusiast but she know that even if he doesn't seem a reliable person, he always protected her and she's fine until now, so Juza is who helps her to reach Rokkenjima in order to find the truth about the tragedy of October 4, 1986, when she lost her family and her life became like the hell.
She's usual to share her pain with him, and during the journey she thinks about a reason to live and to believe in magic. Juza is a hot-headed guy but he's always kind and sensitive with her, she's sincere and determinated. So, even this time, he makes a meaning discuss to Ange, explaining that everyone has a reason to live, and if we don't know what it is, we need to search for it with all ourself, in order to go on building our future. Magis does exist ONLY if you want to believe in it. All is determinated by love, because if you love something, you'll always believe that that thing will be there, if it's the opposite, you'll never believe in this thing even if it exists since always and forever.
Ange always hears Juza's words and she knows that he's sincere.
I think that if Juza could see her smiling just a time, he'll die for the happiness in a second! XD
They find the way to go to Rokkenjima and there Ange understands and finds the answers of her questions, clarifing even with her other aunt, Kasumi, sister of Kyrie (err... Ange isn't lucky with aunts, doh). Here she asks to Juza to leave her alone. After this moment and after Ange's death in 1986, we can see them together in Episode 6, when Ange opens her eyes as if she dreamed the discussion with Battler and Beatrice in Purgatory, and the person that faces her is Juza.
He poked her face with his finger and she's very embarased! So sweet.
When they meet Eatherinne Augustus Aurora, they share other moments together searching for the reason why they're in that place and in that moment, even about her, but after the apprition of that witch, Ange remains alone with her.
It's very meaning that Ange and Juza are alone an together in this game, their future as couple isn't a dream.
Beyond the official story of the game, the manga and the anime, we have another reason to be happy for them, and it's Beatrice's Valentine's Day, an extra game of the 5th Episode in which Ange gifts Valentne's chocolate not just to Battler but to Juza too!
But unluckily we can't know what's he turned to her in the White Day... T____T Also Asmodeus gifted him chocolate (made by Ronove, eh! She likes Juza's body and considers him hot, but she's Asmodeus of the Lust, she doesn't consider persons for any reason but love and sex) and he turned her a little gift.
It's CLEARLY explained that Juza is popular among the girls and it's usual for him to receive chocolate for that day. He always turn something to the girl but it's a little present that DOES NOT means that that person is important for him.