If you can't find a trustful place to buy something it might be a sign that you shouldn't be buying it.
What is it about OMISE that's so attractive? The ICO market is insane right now, and not in a good way.
You can buy on bittrex.com. Good volume.
Bittrex reputation seems solid though, just move carefully. Buy small first and if all goes well you'll have more confidence with a big buy.