Fantasy book about a girl raised as a boy by some kind of monk-warrior society/enclave that is situated apart from the rest of society

Question

Here are details I remember: the main character doesn't know she's a girl; she's being raised by some kind of monk-warrior society/enclave that is situated apart from the rest of society.

There is a life/death trial involved and the main character begins the tale in position to take part in the testing of some new potential "recruit" to the enclave. I believe that men are exiled to this place and, if they survive the trial, they get to stay: failure = death.

The girl has lived all her life as a boy and thinking she was no different from the men of the "monastery". Something happens and she discovers she's been deceived all her life about her sex.

Answer 1

This is Starless by Jacqueline Carey.

The main character's name is Khai, and he is the shadow soul to Zariya Sun-Blessed, a royal born at the same time of a lunar eclipse. The early chapters involve a still-young Khai asking to take part in the Trial of Parkhun - a trial for those trying to escape a death sentence, only to face the warrior-monks of the desert instead. The new Brother Yarit actually passes Khai to pass the trial, although Khai is not harmed. Yarit is actually the one to disclose Khai's deception about his gender, once puberty is at hand and the monks are forced to acknowledge he is different.