how do I tell a gay girl don't like her like that but as a friend

Okay, did she specifically say she wanted to go out with you? I'm not gay so I don't completely know how to go about this, but I'm pretty sure gays can have straight フレンズ whom they don't have crushes on and she'll probably understand that あなた don't like her that way if あなた tell her.

Just say "sorry but I'm strait .but I like あなた as s friend

All あなた have to say is "You're a good friend, but I'm only interested in guys." Don't worry, we レズビアン are quite understanding. And あなた can still be her friend, あなた know. :)

straight girls are gay
straight guys are lesbeans
:P

Like you'd tell a guy who has a crush on あなた but あなた only want as a friend. Be respectful, kind, yet a little firm when あなた tell her this.

Also, did she tell あなた that she'd kill herself? If yes; I don't see that type of statement has romantic, just a sign of needing some help. (Sorry for those who have told their bfs/gfs before)