I see in Japanese

なるほど

naruhodo

fixed

What it literally says

indeed / so that is how it becomes

Japanese politeness is mostly built out of phrases that stopped being literal a long time ago. Knowing what is underneath is the difference between repeating a sound and knowing what you said.

When to use it

Signals that you followed and found it interesting. Very heavily used.

Next in Reactions and Compliments

Really?本当ですか
That's a reliefよかったです
That's interesting面白いですね
That's lovely素敵ですね
That's a shame残念ですね
Well doneお疲れ様でした

What it literally says

When to use it

Next in Reactions and Compliments

The rest of the phrasebook