Male-Female Friendship

What do you think -- how difficult is it for a guy to develop a FRIENDSHIP with a -fairly attractive- woman?
I have been trying to just that over the last two years, and I must say it is a tough going. Not easy at all.
While this woman and I enjoy each other's company and we sometimes go to restaurants, I certainly have the feeling that she is defensive about her (other) social activities and private life. In other words the whole thing is a bit asymmetric, since I try to make the friendship work and she is holding back a bit (though she likes the restaurants I take her to....).
The following factors may play a role:
1. I have a higher education than she has.
2. My financial situation is much better than hers.
3. She is a busy woman, while I have lots of free time.
4. We do not share hobbies or interests.
5. Because of the lack of development, my enthusiasm is diminishing.
I have been trying to just that over the last two years, and I must say it is a tough going. Not easy at all.
While this woman and I enjoy each other's company and we sometimes go to restaurants, I certainly have the feeling that she is defensive about her (other) social activities and private life. In other words the whole thing is a bit asymmetric, since I try to make the friendship work and she is holding back a bit (though she likes the restaurants I take her to....).
The following factors may play a role:
1. I have a higher education than she has.
2. My financial situation is much better than hers.
3. She is a busy woman, while I have lots of free time.
4. We do not share hobbies or interests.
5. Because of the lack of development, my enthusiasm is diminishing.