When Ezra first encounters Maul, he definitely doesn't trust him. He draws his lightsaber on him and tells him to "Stay back!" After Maul says, "You came for the same reason I did, years ago: you seek knowledge" and explains that he knows how to get into the Sith temple, Ezra agrees to go with him but insists that Maul walk in front of him, apparently so that Ezra can keep an eye on him.
Ezra's feelings toward Maul begin to change after Maul says, "The Sith took everything from me, ripped me from my mother's arms, murdered my brother, used me as a weapon, and then cast me aside, abandoned me." Ezra replies, "I know how you feel. The Empire, it took away my home and my mother and my father." As they approach the door to the temple, Maul claims that the knowledge inside is the key to destroying the Sith, and when he says that he'll share this knowledge with Ezra, Ezra starts walking up the steps in front of Maul:
Ezra keeps Maul at a distance when he first meets him, but after Maul entices him with the knowledge inside the Sith temple, Ezra goes before him. This change visually indicates that there's a more or less definite point where Ezra starts to trust Maul.
