This is a very valid point considering the massive domination of the writings of Princess Irulan when it comes to historical texts about Muad'Dib, but there doesn't seem to be much pointing towards any sort of resentment of him so we are generally inclined to take her writing at face value.
Sure, she was probably a bit annoyed that he would marry her for her claim but never even touch her but it seems that this mellowed out quickly. This is also the way we find it in the writings of others of the period, such as the "Journals" of Gurney Halleck or the reports of the Lady Jessica to the Bene Gesserit.
A certain amount of quotes and private events are recounted in other sources fortunately, mostly Stilgar and the two afore-mentioned ones while it appears Chani did not really take to writing much, and if we compare those to the writings of the great Princess Irulan we find that basically all of the things she writes about are effectively matching those other sources.
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