Problem solved.
I added one more state called "checkGround" - and that's where I've put the Line Cast and Bool check.
In the Jump state i added the action "send event", with a 0.1s delay.
I'm not sure this is the best solution, but it does the job. Since the jump-animation stops playing before player reaches the ground... .
Thank you Djaydino and Heavygunner for your help!