In the current game state, it is insanely easy to miss out on Act 3 romance content with Astarion (or have it bug out as it happened with me), if you have a steady rotation of companions in your main party as you are completing Act 2.
No, it's a lie and you know it. You have to go out of your way to not interact with Araj. If you talk to her without Astarion (or place him somewhere damn far so he's not a part of the conversation - so you could buy some things from her) she will ask you to bring him to her. It's impossible to miss. Especially considering the fact she's a vendor with some really good items in stock - risky ring being the star.