How to Use "proof" with Example Sentences

1. With the signed letter , you have proof you left voluntarily . "
2. He doesn 't blame the drillers for demanding more proof . "
3. A few years back , si went looking forstatistical proof or disproof of the jinx .
4. In other words , we are offered " for instance " instead of proof .
5. Can there be stronger proof that amazon 's chief trusts jassy to deliver ?