You don't fight trynd level one. He will crit your health away. His crits will reduce spinning slash's CD and he'll slash over and over.
You may be the cheese that is Fiora, but you're not the level 1 cheese. He's got one of the strongest ones. Your best bet is to ult him and time the ult so that you proc right when he activates his. You'll be healing for 5 seconds as he is invulnerable. Bonus points if you have riposte up, in which case you can dodge some damage and heal up.
Otherwise, don't build glass cannon. Build tanky. No one can out glass cannon Trynd with his ult. Try and poke with Q when his vital is easily accessible. Use best judgement if it's wise to activate E and get the crit off, or if you should pull out before he has a chance to out trade you.