Rachel McCord is a Federal Government Agent and former partner of Kate Beckett, when she first becomes a federal government agent. McCord seems to have considerable respect for Beckett, as proven when she openly lied to their boss, Carl Villante, and even trusts her judgement. Not only that, but she's also a good moral judge of character especially when it comes to intervening and where the federal government cannot do so, being smart enough to not let it become a matter of her own ego. This hostility from their first meeting would cause her to have a great disrespect for Castle.