Unable to make up her mind

I've been in a strong relationship for the last two years with a wonderful woman. I should point out that she is of a different nationality, and in the country where we live, it is very uncommon for people who are not married to live together. Until about November, things were going well. We were seeing more of each other than ever, despite busy working schedules. We were both making a real effort with making the relationship work. We have hardly ever had a crossed word or an argument, and other people complimented us on being a very happy couple. For a long time, she has been keen on marriage and having children together. She is of that age where women feel that time is running out for children, and she would frequently talk about her desire to have children and get married. I was very happy with this arrangement, but explained that we needed to get our finances in order and I wanted to spend a little more time with her family. I was very clear that it would happen... and soon. Anyway, Christmas rolled around. She had been extremely busy working and had been ill, and I had also had a lot of things to do. We'd not seen much of each other compared with the rest of the year. We keep in regular contact, send lots of messages by phone and call frequently too. I am very confident she's been a good girl. Anyway, Christmas came and my present was what I was sure she wanted... an engagement ring. I spared no expense and did her proud, and I have been waiting for the right moment. Unfortunately, I still have the ring. A few weeks before Christmas, she said she wanted to get over her sickness. She had been ill for a little while, so it was very reasonable that she didnt want to see me as much. Time passed, and further excuses kept on coming, she was busy with work again and so on. Eventually, she said she wanted a bit of a break. She didn't explain it very well, and i questioned her, but decided to give her what she wanted. We've kept in touch, but haven't seen each other. She had told me she likes me a lot, but she is now unsure about marriage. She said one day she thinks marriage is a great idea, and is really happy with the idea, and then the next she is just keen to get away from it. She thinks, because i am so keen on marriage its not good for us to stay together and prolong upset and disappointment. I've made an effort and we have met a few times, at first against her wishes. She claims she loves me, and thinks i am a wonderful person, but she is just unsure about her direction in life. She claims she can't really love anyone, and its nothing i have done wrong, she is just confused in her mind. I've said we dont need to rush anything, and I will be happy to go at her pace, providing she gives me a chance to prove my worth. I realy think this potential marriage is worth saving. I spoke to her sister about it, and she said that I should continue doing what i am doing and hope for the best. They are very close, so i value her judgement on this. Women!