Looking for a Manhwa

So this manhwa is about a girl who is originally in this church maybe studying for this big exam. She decides to join the war where she heals a friend in battle that was on the break of death, but instead of just healing him, she ends up healing everyone on the battle field including the enemy. I think she may have at some point confessed to the ML on the edge of a cliff because she didnt want to die. Thanks in a advance!!