The Eve of St. Agnes Stanza 14

"St. Agnes! Ah! it is St. Agnes' Eve—
Yet men will murder upon holy days:
Thou must hold water in a witch's sieve,
And be liege-lord of all the Elves and Fays,
To venture so: it fills me with amaze
To see thee, Porphyro!—St. Agnes' Eve!
God's help! my lady fair the conjuror plays
This very night: good angels her deceive!
But let me laugh awhile, I've mickle time to grieve."

• Angela thinks that Porphyro's mentioning the holiday because it'll make it less likely that Madeline's family will kill him. She's quick to disabuse him: "Nope—they're just as happy to murder you today as any other day. And that would be very, very happy, for the record."
• Once again, we have an invocation of fairies: Angela can't even believe Porphyro got into the castle unscathed, and says that he must be some sort of elf-king, capable of witchcraft, to have pulled it off.
• Angela thinks that this whole plan of Madeline's to see her future husband is silly, and she laughs about it.
• It's kind of funny that she calls Madeline a "conjurer," though—so far, the St. Agnes' Eve rituals have been described so that you have this idea of Madeline making herself totally vulnerable so that she can be receptive enough to get a vision from heaven. Here, though, Angela makes it sound like Madeline is herself controlling the ritual, as if she's a magician pulling a vision out of her hat. 
• Angela thinks it's all baloney: Madeline's putting her trust in a worthy saint ("good angels"), but this whole presto-magic-vision thing ain't gonna happen, if you ask her.