Elkar was not afraid of Amara. He knew that Amara would not be able to do much as she is now trapped around the Godstree.
She could do some stuff but she clearly would not be able to harm him. So, he was not that fearful.
However, he does feel wary.
Why would Amara contact him? Even though Astiel and Jurgan had chained Amara, Elkar himself had never met with the Goddess of Love.
So, he is curious why would the Goddess of Love would try to meet with him
'Is this an attempt so that I would help you?' He asks Amara. He was quite straightforward.
This is the only possible reason, he thought to himself.
From what he knows, Amara is probably trying to use him so that he would release her from her bondage
Astiel and Jurgan would surely not fall for any bewitchment of the Goddess of Love. However, he is different.
Maybe that is why, she targeted him.
And he could not help even if he wants to.