Question: was Cissnei supposed to be competition for Aerith?
Japanese version
Zack: Anyway Cissnei---Do you think you could talk to my mother for me?
Cissnei: That's true. It'd be my pleasure.
Zack: Just don't say anything that would make them think you're my bride to be.
Cissnei: I've already told them.
Zack: How could you tell them something like that! Cissnei!
English version
Zack: Hey, Cissnei... Would you mind...keeping my folks company for a while?
Cissnei: All right. No problem.
Zack: They'll probably ask you to join the family.
Cissnei: Already happened.
Zack: What did you say? Cissnei!
I forget but I think this site has the translation of either CC Ultimania or CC Complete Guide, I just remember I read somewhere that Cissnei indeed has feelings for Zack but it's unrequited. The devs make the beach scene for referring the female friends Zack has that makes Aerith's jealous as interview below:
From Dengeki PSP Vol. 397
- In the beach scene there's a good atmosphere between Zack and Cissnei, but what's kind of relationship did they have?
Nomura: "There was a scene in FFVII where Aerith says something about Zack having other girlfriends."
Tabata: "It's meant to allude to that. Besides that, she's also one of the people who gave Zack support along the way. Some of those feelings are depicted in the DMW memory scenes."
“A guy who loves girls a lot” – That was what Aerith reflected on in FFVII, that Zack had a flirtatious streak, and was experienced in the treatment of the fairer sex. In BC, he gave compliments enough to set one’s teeth on edge to a female Turk member who was together with him on the same mission. As expected, there was a scene whereby he invited Cissnei, a young lady from the Turks, to a meal in CC. As a result of being able to surmise everything from each small deed, Aerith, who was in love with Zack, might perhaps have been jealous many times seeing all that… –Zack’s Profile 10th Anniversary Ultimania
But you see in the actual scene, Zack not givin' fuck at all to Cissnei who is totally in bikini. He's even bored and tells her to go because he wanted to call Aerith!
Zack’s “I’ve managed to get a girlfriend” letter was left out in the parents’ home. If it was 6-7 years ago, it was about the time where he met Aerith in CC… Does that mean the girlfriend was Aerith? Zack seems to have a number of female friends, but especially informing his home means there’s no doubt that the partner is a
SPECIAL one.
Aerith, the girl whom he met at the slum’s church. The existence of the girl, who had earnestly come to love Zack with sincerity, eventually became irreplaceable to him.
(Zack’s Profile, FFVII 10th Anniversary Ultimania)
Just as Kunsel tells him not to “just read mail that he gets from girls” in Scene 01-04, Zack’s flirtation leads to Aerith calling him a “ladies’ man” in “FFVII”. Zack himself, while on the run from the Shinra Army after the Nibelheim Incident, also talks to Cloud about having several female friends in Midgar who might be able to hide them. Indeed, he hits on Cissnei and the receptionist in this game, and the female Turks in “BC” when they met for the first time. However, Aerith alone appears to have been truly special to him, and he tells his parents in a letter that he found a girlfriend (Aerith). –Crisis Core Complete Guide