"Empowering Advanced Learners of English in Business and Academia - TOEFL / ESL / EFL"
Video example (click "CC" to view the text as it is spoken)
When it's hard to distinguish between two competing things, emotions, or situations.
Context : Emotions, Social Life
Usage of “a thin line”
It's a thin line between tough love and abuse.
Examples of idiom “a thin line” from Twitter
"Its a thin line between, love and hate...and even, a thinner line between real and fake" - C Note