How to pronounce 當真 in Cantonese (3 out of 5):

其實揀呀你哋唔好真係當真
You guys are not really real.

Cantonese Sentence Breakdown

其實 kei4 sat6
actually
gaan2
choose
haa1
(particle equivalent to 啊 after a vowel, expressing surprise or doubt)
你哋 nei5 dei6
(pronoun – plural) you
唔好 m4 hou2
(phrase) don't.
真係 zan1 hai6
really; very
當真 dong1 zan1
take seriously