Isekai No Seikishi Monogatari summary:

Masaki Kenshi was taken from his home and was sent with a combat suit to assassinate the young queen Rashara. His mission was unsuccessful and he was captured and would have been typically executed for such a crime. However, Rashara, seeing that Kenshi was forced to carry out such a mission, pardons his life. She allows him to stay at the pilot academy and he becomes friends with many of the women surrounding Rashara. However, there are deep secrets that may threaten the comfortable life that Kenshi is living right now.