But she doesn't care about him emotionally. That's not her motive. So she wouldn't hurt him just to hurt him.
She's after a leader for the Hand, so she says. Perhaps she's separating Matt from his straight and narrow life, so that it makes sense for him to lead the Hand--to prevent them from doing evil. Elektra had similar thoughts when she first joined. Or maybe it's a roundabout way of getting Wilson Fisk to lead the Hand. ::shrug::