she is not even thinking of getting reaasurance about her status in Alekh's life, she is already thinking how to put Alekh on the right track...because Alekh is just damn upset now...Alekh needs to calm down and when a person calms down, then only he can think staright... Vasu has done wrong, but that does not mean "just abandon her"..
I thought you meant about trust also. And but the same still applies....Sadhna is not a ordinary character. She has a very big heart that she can think about the feeling of her enemies as well. Vasu may have done alot of things to her, but for Sadhna she is still her mother. She doesn't want to be the cause of stealing a son away from his family. Just like Mamaji in many situations. Sadhna's ethical and standards, will not allow her to do that, even if its the son's own dicision.