ほんま

really; truly

Word type: 

Standard: 

ほんとう

Standard kanji: 

本当

Example: 

A: あんた、どこ行ってたんや。
B: 吉田んとこで勉強してたんや。
A: ほんまかいな。
B: ほんまほんま。明日、テストあんねん。

A: Where were you?
B: I was studying at Yoshida's.
A: C'mon, really?
B: Really. I have a test tomorrow.

Commentary: 

A very common word in Kansai--pretty much the word to symbolize Kansai-ben.
ほんま can be used as a back-channel? (aizuchi).