We know Regina is, or was, good with kids, and really wanted her own. However, when she made the curse, she created in herself a void that could not be filled. Henry was given to her to fill that void, yes, but it still cannot be filled.
So, although I do think that Regina may love Henry as her child, I don’t think she is even physically or mentally capable of completely loving Henry to the extent of true love because of what she had to give up to create the curse.
BUT will she be able to overcome that? I think there may be a time in the series where Regina has to choose between good (saving Henry) and evil (letting herself live, killing Emma, re-enacting the curse, etc.). But this time, she will be unsure of which way to go, unlike her cruel willingness to kill the thing she loved most in order to get what she wanted.