If you do this properly you can W and dodge his stun.
You both have no ranged poke so he can't kite you.
You want him to use up his corrupt pot stacks as much as possible as him surviving your bleed stacks thanks to it is the most tilting thing on the planet.
You just place your E and after he combos you what is he going to do? Tryndamere's spin is a 12 second cooldown, meanwhile jax's counterstrike cooldown is 16 seconds level 1.