It will be converted automatically. If select your native currency, your procedure of payment will stopped and you will have the same situation as you had before with LiqPay, OnPay, and whatever.....Pay
Did you read the quotation at the bottom of the page? Did you read that the user paid also in Ukrainian Grivna and his payment was processed within minutes? If you make your own, don't ask here- what happened. Follow procedures described in the manual.