He knows and any half-decent lawyer will make mincemeat out of that confession.

黛安：他知道，​​任何一个半正经的律师都会把那份供词弄得一团糟。

Diane says, " He knows" – the suspect knows – " and any half-decent lawyer will make mincemeat out of that confession." " Half-decent" means pretty good – someone who is not the best but good enough.

黛安说，“他知道”——嫌疑人知道——“任何半正经的律师都会把那份供认弄得一团糟。 ” “半正经” 的意思是相当好——一个不是最好但足够好的人。