[Just -- he knows you're capable of a lot of things. This has just brought it forward, and while before he admired her ability to get things done, to do what she needed to in order to survive in her world, to protect her daughter, and all that... now it's a matter of considering the part where it means Aramis could be harmed or put in danger, or anyone else he cares about; now it's a matter of finally seeing some parallels between Milady, and how she still has a hold on Athos]
... I only want to protect the people I care about. [And if that means being suspicious of you, then he will be. But he doesn't want to be.]