How to say "但是这事得跟你说一下" (dàn shì zhè shì dé gēn nǐ shuō yī xià) in Chinese dialogue

dànshìzhèshìgēnshuōxià

But I need to tell you about it.

Idioms & Colloquial Expressions
Grammar Patterns
INTERACTIVE SCRIPT TIMELINE
LINE 0135:15
méi
shén
me
shì
fǎn
zhèng

It's nothing big.

LINE 0235:18
PLAYING SCENE
dàn
shì
zhè
shì
gēn
shuō
xià

But I need to tell you about it.

LINE 0335:19
shì
zhí
dāng
jǐng
chá
ma

Haven't I been a cop all along?

Show Information
Source MediaTV Series
Season & EpisodeS1 E7
Timestamp35:18
TMDB ID282902