My sister's keeper Question?

during the conversation about kate, zanne tells sara, :no one has to be a martyr 24/7". when she mistakenly haers the word "mother" no " martyr" and is corrected bu Zanne, sara smiles and asks, "Is there a difference?" in what ways does this moment provide insight into Sara's state of mind? Do you think it is strange that she sees no difference between motherhood and martyrhood?