I met a woman at the Ukrainian Diamonds, we communicated for months, and have a lot in common. I would like to marry her, but is it okay if I propose her before we meet? So I don't spend any money for visit if she says 'no'.

That would be a big "NO".  You need to meet and spend time with her in person before you'll really know how you feel about her .. And her about you.  Sounds like you're more interested in not wasting your money than not wasting your life with someone you hardly know.  Marriage is a huge step and well worth all the time and effort you can put into making sure it's right for both of you.  Divorce is very expensive you know.

NO

She could be a MAN.

Live in Nigeria and be a man.

Be a teen.

Be a married woman or man.

Be a married man.

Be in prison and have someone else writing you and be a man.

Or be a woman out to scammed you.

If you're not happy with my answer refer to all answers above me.

My final answer is NO.

Maybe you need to see the show Catfish. It will clarify why you need to meet the person first.