(Manga spoilers)

So basically I just want to point out how much trust, faith, and love that Armin still has for Eren! Armin's dream, world, everything was Eren. If Eren wasn't with him then he would have no meaning to live, or to see the ocean. That was very clear in season 1 after  Eren saved Armin. Also very clear in season 3 part 2! If that doesn't scream love, then I don't know what does!!! Anyways...

Chapter 110: After Eren escapes from jail, everyone is shocked and doesn't know what to think anymore. They're losing hope for Eren. Even Mikasa. While Armin is indeed in the same state as everyone else, he's still reassuring Mikasa that Eren will understand them if they talk. He just wants to believe in him so much.

Chapter 123: Right after the walls crumble, Armin is screaming at Mikasa that Eren is going to crush the allied forces in Marley, and that Eren is on their side! You can tell that a lot of his screaming is just him trying to convince himself. Yes Eren is on their side. He wants to kill all the other people outside the walls for their sake! While on the other hand, Armin doesn't want so many people to die. However, Armin doesn't hate Eren for this.

Chapter 124:
Armin knows that Eren is doing this for their sake. Again, Armin doesn't agree with killing hundreds of thousands of people for the sake of their freedom, but he seems to understand where Eren is coming from by the time Jean is done talking to him. Though Armin doesn't agree with him, he still loves and cares about him. That's never changed like I've been seeing some people say! He's still defending him!! Just look at this part!!

Gabi is asking why Eren can't just turn everyone who's a titan back into human. Armin defends him by basically saying, if he could he would! That soft expression on his face!! Even after chapter 112 happened, Armin is disregarding that because he knows Eren loves and cares for him and everyone else. Armin knows Eren's heart better than anyone, as he once said himself before. This is enough to show just how much love, and faith Armin has for Eren! He loves him so much!!💗💗💗

What Eren is doing may not be right, but it's not wrong either. What Eren is doing is understandable, and you can empathize with him on a serious level. In the world they're living in there's no right or wrong way! Eren is just doing what he thinks is right for the people he loves! Protecting his loved ones, and their freedom no matter the cost!!