It can be difficult, if body language and mating/dating customs are different between cultures, to show your interest in someone in an appropriate way. Is there someone she knows from within the man's race/culture, whose advice she can ask as to what his expectations would be from a woman who wishes to show her interest? Posting the question here and on other forums is a good start.
But in my experience, the only real way to find out if a man is interested...

It can be difficult, if body language and mating/dating customs are different between cultures, to show your interest in someone in an appropriate way. Is there someone she knows from within the man's race/culture, whose advice she can ask as to what his expectations would be from a woman who wishes to show her interest? Posting the question here and on other forums is a good start.
But in my experience, the only real way to find out if a man is interested in you, is to ask him out. If she's not comfortable (or thinks he may not be comfortable being asked out by a woman) then she could set the ball rolling by letting a friend of his (or colleague, or a fellow member of a club, church...etc.) know that she would be positive to an approach from him.
Men - from all cultures - are often so afraid of rejection and ridicule, that they won't ask a woman out unless they already have reason to believe she is interested.
Also, having a "crush" is one thing; but you can only find out whether you really respect and like a person enough to really fall in love with them (in a healthy way), after having spent a fair bit of time together. So she will have to start dating him at some stage. She may also be afraid of rejection (who isn't?) but the tactful intervention of a third party can test the water and help save face all around.
Love is so fraught! isn't it?...the heart is such a vulnerable organ! You need courage to follow your feelings. I hope she remembers always, to believe in herself; that her self-worth cannot, in the end, be determined by another person.
Wish her luck from me, and let us know how it turns out!

Why should race change the way she would show someone she likes them? Just let the PERSON know of the feelings. If color changes the way she acts at this point, I'm not sure of how it will work out in the long run.

I am with yokozuna but i have to say different races do have a different approach to love due to traditions and customs she should just say she likes him although she has to be careful as some prefer their own race, this will have to be a leap of faith and she wil have to be prepared in case she get's hurt but it is very unlikely i wish her luck!!

At 33 I am sure she knows how to flirt. I would say some harmless flirting for starters. This will see if he is open to the idea and then she should just say... " you know we should go see........." [fill in with something of like interest - a movie, or band, etc]

I think your neice should just tell him how she feels. She should just be herself. If she feels that she has to approach this person in a "special" way due to his race/culture, then she needs to ask herself if she can really be herself around this person.

Good luck to her!