I would really appreciate if i could see when someone reports me :)

You can, you have to pay though, privacy.riotgames.com enables you too. You can see how much you have spent and statistics for free but you can pay 5$ and see this

Why?

Actually it used to give a warning like:

you playing this way seems to be going against the summoners code etc.

It was frustrating to receive as toxic people just used it on everybody.

There is no reason to know when people report you as that leads to the possibility of you reporting people in retaliation and/or harassing them about it after the game. If your behavior was bad, the onus is on you to recognize that, not on Riot to babysit you.