How do I handle sending people into danger?

You can lead. That part you have proven. What still floors you is the moment you give an order that could cost someone their life. If that ever stopped weighing on you, you would be the wrong person to hold the position. The weight is not a weakness. It is your conscience doing its job. The fear of it will not leave, and it should not. But you can change your relationship to it. You are not the only cause of what happens out there. You make the best call you can with what you know, you prepare your people well, and then the world does what it does. Your job is the decision, not control over every outcome. Before the next hard call, do one concrete thing: make sure the people going in have what they need and know why. Then, whatever comes, you can stand on the fact that you led them honestly and prepared them fully. That is the part that is yours. Carry that, and let go of the part that never was.