"Then I suggest you consider the options between yourselves," Alarich says, opening his arms in a wide gesture. "If I am to move east, I will need all my men for the journey, and I can't commit them to any sort of attack on the warforged. If you won't guarantee a safe passage west to the Princess, then I'm afraid I don't see how I can help."

He doesn't seem to hold any particular preference either way, nor any ill-will over whatever decision you choose to make, but perhaps that's just his monotone voice dispelling any emotion.
"If you would like time to discuss it, I can step out of the room? There are other matters that require my attention - preparations to make, regardless of how you want to proceed."