French singer-songwriter Zaz uses the verb essayer (to try) a few times in her interview on Watt's In, and it's conjugated in two different ways:
Enfin j'essaie toujours de faire du mieux possible.
Well, I always try to do the best I can.
Cap. 72, Watt’s In - Zaz : On Ira Interview Exclu
Mais au moins tu essayes...
But at least you try...
Cap. 77, Watt’s In - Zaz : On Ira Interview Exclu
Why do we have j'essaie (with an i) and tu essayes (with a y)? The answer is that the spelling of many conjugations of essayer is variable. Here's the verb in the present indicative:
j'essaie or j'essaye (I try)
tu essaies or tu essayes (you try [singular])
il/elle essaie or il/elle essaye (he/she tries)
nous essayons (we try)
vous essayez (you try [formal/plural])
ils/elles essaient or ils/elles essayent (they try)
Whether you spell the variable forms with an i or a y is completely up to you (except for nous essayons and vous essayez, which you must spell with a y). However, there's a bit of a catch: the pronunciation of the verb changes depending on which spelling you use. You can hear the difference in the two captions above: Zaz pronounces the -aie of essaie as a short "e" (as in mai, "May"), and the -ayes of essayes as a longer "e" (as in pareil, "same"). That's how we knew to spell them the way we did.
In fact, pretty much all verbs ending in -ayer follow this pattern. Listen to Patricia demonstrate the difference between je paie and je paye (I pay) here:
Petite particularité pour le verbe "payer": on peut dire "je paie avec ce billet" ou "je paye avec ce billet".
A small particularity for the verb "to pay": you can say "I pay with this bill" or "I pay with this bill."
Cap. 31-34, Le saviez-vous? - Les verbes du 1er groupe les plus utilisés - Part 1
Variable spellings don't only occur in the present indicative form of -ayer verbs. You'll also come across them in the future (e.g. vous paierez/payerez, "you will pay"), in the present subjunctive (qu'ils essaient/essayent, "that they try"), in the present conditional (tu paierais/payerais, "you would pay"), and in the imperative (essaie/essaye, "try!").
Some other common verbs that follow this pattern are balayer (to sweep), bégayer (to stutter), délayer (to mix, dilute), effrayer (to frighten), égayer (to cheer up), and rayer (to scratch, cross out).
See this WordReference page for a full conjugation of essayer and other verbs like it.