I agree with Darion, it's very hard to answer without knowing more. Does he know about Trumpet Blast? What cards does he have in hand? I'd probably consider your attack a desperate attempt to bluff or race. AFAIK, there is no single card trick that makes this attack favorable, which makes your attack a doble trick or a bluff, or possibly Planar Cleansing. Either way, it is almost surely correct to block, but maybe only with the 2/3 (though that won't help against 2x Trumpet Blast). He still has you on a 2-turn clock even if you manage to kill his 2/3.