Good evening, I would like to assist you today. What kind of emails is she sending to him?
I would first recommend that you have a solid reasoning behind why you say the boy does not like her. Did he tell her this, or is it from how he responds or doesn't respond to her why you say this? Yes, it is more typical of girls to play hard to get, and ignore a boy, even if they really like them, but boys on occasion can do this to the opposite sex as well. If she is aware that he doesn't like her, perhaps because he has told her, explain to her how desperate she looks sending him emails, although he has already expressed he doesn't like her. Let her know that she is too beautiful and talented to chase after a boy who doesn't like her. Also, if he has already said he doesn't like her, if all of a sudden he appears to give in, and to like her as well, it could really be just a way to use her.
If the issue is that you think that he doesn't like her because of his ways and actions toward her, you must remember that at their age, a boy may intentionally tease ore puck fights with a girl when actually he really likes her. It may be a good idea in this case to recommend that she not send him as many emails. I definitely do not suggest trying to tell her not to email him; this may be cause for her to go against what you say. If you really don't think that this boy likes your daughter for a good reason, express the reason why to your daughter, but don't try to be dominating or controlling about the conversation; try to keep it as a calm and balanced as possible. If she doesn't agree with you, don't make a big fuss about it, just let her know you respect her view, but as her step parent (which is what I am assuming you mean), you do love and care about her, and you just wanted to make her aware of what you were seeing
Assuming that you meant "step daughter" when you said "half daughter", I also suggest that you get your spouse, her actual parent to ask the questions, make the statements and speak to her about this. Your role of course would be to verify what your spouse is saying and chime in here and there with points you may want to mention. It may also be true that your daughter just has to learn the hard way about this situation. The best that you really can do is voice your opinion to your daughter in a non dominant way, and be there to listen to her and provide advice when she needs and requests it. If you have any other questions, or if I have not provided the answer that you need, please message for "earthsister". Thank you.