Does the target know about the spell if it failed the saving throw?

[Zeffire]

I apologize immediately for my English. There was a question about how spells work on a person. Specifically Charm Person. Will a person know that a spell was cast on them if they failed a saving throw at the end of the spell?

Provided that he didn't see or hear the caster. In the rule book, I found a description of only if there was a successful saving throw, the person will feel the impact.

[avr]

If they fail the save they won't know about the charm person effect during the spell. Afterwards they may figure out that they were charmed from their memories.