After becoming a Martial Saint in just a few months, her talent was deemed to be one of the strongest in Illevis's eyes. Upon knowing it, she gave her a few million Spirit Crystals, wanting her to take the opportunity to cultivate even faster.
Aria, of course, had no intention to reject it. She simply received the Spirit Crystals and brought them to Alex. But to her surprise, Alex didn't take even a single Spirit Crystal, letting her use all of the crystals.
Alex was a God Rank Expert, so he needed far more than her. And the fact that he took half of the reward they got from the previous mission made her think he needed money.
Alex only told her that they would split if the money came from their joint efforts. If it were her alone, he wouldn't touch her money.
Having this agreement, they proceeded in their training, planning to show even more progress, so Illevis would come again and give more resources.