Pronounced: iss DOH-kha nokh will SHANSS er bih OW-n
Actually, the phrase comes across as much more polite in Irish. A better translation would be "It is certain that there is no chance", or less literally "I suppose there's no chance..." . The subtext is clear, but you'd be much less likely to be slapped across the face for using the Irish version.
You's also have the advantage that the chances of the person from whom you are soliciting sex being a fluent Gaelgeoir are pretty damn low. If however, you really wanted to offend them, try "Is dócha nach bhfuil seans ar bith agam oíche fiachmhar salach a chaitheamh leatsa?". And no, I'm not telling you what that means.