She hasn't been here long enough to be more than 'a senshi' to him yet. Now, what does that mean?

It means he really does not respect her. He understands faith and trust - the only guiding force in his life in his belief in the prince - but he also knows the consequences of that 'Oh it'll work out' without a lot of work and determination and hard choices. So far, he hasn't seen the senshi demonstrate that capability; and in his world, they won't until it's too late.