Soliloquy - A person's most inner thoughts, they speak them on stage but they're the only ones who can hear it.
"Commends th' ingredience of our poisoned chalice to our own lips. He's here on double trust"
To me this means praise formally the ingredience of our poisoned cup to our own lips. Macbeth is there on double trust. In Macbeth it shows that Macbeth was planning something devious against Duncan and Malcolm like poisoning them. Malcolm and Duncan trust Macbeth but the double trust thing is Malcolm and Duncan trust Macbeth but Macbeth is going to turn around and try to kill them so he can get what he wants and become king.