Background:
I am an engineer, but I like to do more than that. I have some hobbies that also bring some extra cash. My wife, on the other hand, she doesn't work right now. She is looking for a job, but unsuccessfully so far.
A few weeks ago, while reading some information about one of my hobbies, she read as well and then she asked if I could teach her that. I've explained some things about it to her and then I've asked her if she likes it, because there is no point in doing something if you don't like it. She said that she loves it. I again said that there are plenty of things to read as it is a vast field, and you need to spend much time in order to learn something that could turn profitable later. She said she'll do it. Time passed, she read a bit but it's not even 1% as she should've, considering she wants to make money. I've told her that she really needs to be more disciplined, to read more, practice more and focus more. Every time she said that she'll do it, but... not now.
In the end, I've told her that in this way, she'll never learn it. Obviously, she got mad at me. I've tried to explain that it's not that I'm not supportive, I am, but she really needs to spend more time to learn and practice these things as they are really difficult. I also helped her and explained every time she asked.
My question is: How can I motivate her to study a field more that she said she likes and would like to try?
PS: I accept tag suggestions, since I don't even know where to put the question.
EDIT:
Q: Does she have trouble understanding the subject on a (to her) satisfactory level?
A: There isn't something too difficult that she could not understand. And she hasn't shown signs so far. When she didn't understand something, she asked. I've explained and she moved forward.
Q: Are you confident your wife genuinely wants to pursue the hobby with the same zeal as you?
A: Yes, I haven't forced her, as she had the initiative. I only explained that if she wants to be a pro, she needs to spend more time learning, otherwise it's a waste of time, since she won't know enough. We had a serious talk on this matter, and she said "Yes, I'll do it!" a few times already. Those were the moments when I've told her that she needs to study more in order to get there.