GRAMMAR DETAIL

ただではすまない

will not end without consequences

Strongly warns that a problem will not end without a price being paid or a punishment imposed.

Examples

証拠を隠した以上、ただではすまないだろう。

Since he concealed the evidence, he will probably not get away with it.

規則を破れば、ただではすまない。

If you break the rules, you will not get away with it.

会社の金を勝手に使えば、ただではすまない。

If you use company money without permission, you will not get away with it.

Structure: ただではすまない warns or judges that wrongdoing or trouble will bring consequences rather than pass without a price.
Basic usage: 規則を破れば、ただではすまない。 warns that breaking the rules will bring serious consequences.

Prediction with だろう
- ただではすまないだろう expresses the speaker's prediction that consequences will follow. Stating it without だろう gives a more direct warning of those consequences.