Alex was happy for sure; just the fact that Ann was at the hero's party was enough to let him know that she wouldn't be facing any problems that she wouldn't be able to deal with.
If a hero was summoned into a despairing situation, then he would gain all the support one could ask for; that was just how it went, so Alex knew that Ann, being a party member of the hero of humanity, wouldn't have a problem.
At least not until she went out to fight against the enemy of humanity—the demons and demonic beasts.
But being relieved didn't mean that he was going to ignore more pressing issues in front of him.
That was the reason for his eyes to shine with utmost seriousness.
About his facial expression, though…
Well, let's just say that he was happy to hear some positive news from someone other than Sophia about Ann.
Creation is hard, cheer me up!