預かって(あずかって)いた為替の(かわせの)「公金(こうきん)」の封印を(ふういんを)切り、手をつけて(てをつけて)しまったこと

Losing his mind out of anger and shame at Hachiemon's words, Chubei broke the seal on the 'public funds' (a large money order) in his pocket. In those days, touching someone else's public funds was a capital crime punishable by death. However, he took the path of no return and completed Umekawa's ransom with that money.