Please note: I have no qualifications in Anglo-Norman, or in fact in any form of French. The following translation is intended as a fun exercise, not a rigorous scholarly undertaking, and accuracy and finesse are in no way guaranteed.
Anglo-Norman Letters and Petitions XL, p 40: Margery to the Archbishop of Canterbury.
To the most reverend father in God and her most gracious lord, Margery, wife of W.G. of London, humbly supplicates that, having wedded the said W. and lived with him in legal matrimony for four years, and not having been contracted to any other man before the nuptials were solemnised between them, the said W., thinking falsely to be separated from the said supplicant by means of a false conspiracy between him and one Robert C., clerk, has feigned a false charge in the court of the most reverend father in God the Bishop of London, and there has pronounced to the said supplicant that she must have made a precontract with another man, when the said supplicant has no knowledge of any such man on this earth, and by means of this charge the said W. has pressed an annulment between himself and the said supplicant, which annulment, through the false supposings of the said Robert, will be carried out, if no solution may be found by your lordship, and so may it please your most noble paternity, for the salvation of W.'s soul, to ordain remedy in this case. For God and in the name of charity.
Original text from Anglo-Norman Letters and Petitions from All Souls MS. 182, ed. M. D. Legge, Anglo-Norman Texts 3 (Oxford: Anglo-Norman Text Society, 1941). 40.
Firstly: please father, save my marriage, for the sake of my bastard of a husband's soul? This lass needs to go have a serious chat with Maude about taking charge of her own life.
Secondly: ymagenant, ymaginacions. This word appears twice, and makes the task of determining just what her husband is about rather a slippery one. The first occurrence is when we are told that W. is ymagenant fauxment d'estre departi de [Margery]... par faulx conspiracie par entre luy et un Robert C. I have translated ymagenant here as thinking, both because it lets me preserve the syntax of the original and because it's a rather neutral word and I wanted to keep discussion of implications out of the text itself. And here she uses it rather neutrally - the moral weight of that phrase is, or seems to be, on fauxment. She could have written creyent for ymagenant, without altering the sense of the phrase - in fact, I'll go out on a limb a little and say that this part reads as if she is trying to excuse her husband and lay the blame on Robert. It's perfectly possible to read ymagenant here as a blameless creyent and faulx in its sense of mistaken, incorrect, erring.
But then we come to the second use of the same word: le quel devors par faulx ymaginacions de dit Robert serra parforny s'il ne soit remedie. The two words again, faulx and ymaginacions, but here the context changes their reception. My first thought here was imaginations, fantasies, the lies Robert comes up with about her life, but the second, hard on its heels, was machinations. And indeed, on consulting the Anglo-Norman dictionary, I found it notes that "there is semantic and formal overlap and/or confusion between imaginer and machiner", defining imaginer as
v. a. 1. to imagine, envisage, create a mental image of; to imagine, conceive, think up 2. to invent, make up; to devise, contrive 3. to plot, scheme (cf. machiner);So, if Margery is (consciously or otherwise) exploiting the ambiguity inherent in this word, this darkens her fau[l]xs to their more negative moral interpretations: wicked or sinful, rather than mistaken. This casts a different light back on what she was thinking when she wrote that first ymagenant, even if she meant to avoid laying the blame on her husband: paranoia, anger that she can't allow herself to feel properly, vulnerability, witnessing a conspiracy that she can neither expose nor withstand? She is concerned to keep her husband from falling into mortal sin, begging the Archbishop to save his soul, but even if she seems to try to keep most of her fau[l]xs from pointing directly at her husband, I think in her eyes his moral state is already fairly questionable. Or perhaps she wavers between seeing him as victim and agent.
v.n. 1. to imagine, envisage, create a mental image 2. to assume, think 3. to make plans;
This man does not make a good head, Margery. Use your own.
 'Ymagenant' - but see note above.
 'E[s]t' - I'm not sure why the editor has added that 's', as in context it can't be a verb, and while 'et' (in the sense of 'and') is sometimes spelt with an 's', 'et' is more common.
 Yes, she really does use 'fau[l]x' three times in a row. And while the double negative of ad feyné une faulx cause sounds clumsy in English, I'm leaving it in there to preserve the sense of vehemence or desperation that comes with the lady protesting too much.
 'Devors', but he seems to be seeking to declare the marriage invalid altogether on the grounds of an earlier contract, not to be granted what we would call a divorce.
 'Ymaginacions' - again, see note above.
 While 'and so' is necessary to make the grammar scan in English, it doesn't appear in the French. Her plese a vostre tresnoble paternitee... ordeigner remedie should, according to the usual form of these petitions, refer back to her opening que come ele ad esté espousé; but that has already been closed long ago, with ore le dit W... ad feyné. Technically, I think this is a grammatical flaw (unless I'm missing something); but to me, looking back at the other petitions, it seems more that the patterns within this form are becoming figures of their own. You open with supplie que, come... and close with plese a vous, and in the middle you tell a dramatic and poignant story in one long, involved sentence, but by the time you reach plese a vous you've forgotten what you're referring back to, and the form stands on its own.