そんなこと言わない

don't say such things

→ そんな
phrase Rare #40,591
don't say such things A casual way to tell someone not to say something like that. Depending on context, it can also mean “wouldn't say such a thing.”
JA: そんなこと言わないで、落ち着いて話そう。
EN: Don't say things like that; let's talk calmly.

賢い人ならそんなこと言わないでしょう

A smart person wouldn’t say something like that.

私だったらトムそんなこと言わない

If I were you, I wouldn't say something like that to Tom.

そんなこと言わない

Don't say things like that.

— 万引き家族 (2018)