What is the ruling on swearing upon the Qur'an to one's husband regarding a childhood rape incident? Can Istikhara prayer be beneficial in this situation? And is it possible to find an understanding husband?

You must conceal what happened to you concerning the rape when someone proposes to you. This is not considered deception unless he stipulates virginity, in which case you should inform him that you are not a virgin and suggest to him that there are many reasons for the rupture of the hymen. As for swearing falsely on the Qur'an, it is impermissible and a major sin. However, if you are forced to do so to avoid divorce or the husband's suspicions, it is permissible with equivocation as much as possible, and there is no sin upon you as long as your intention is to preserve the marital relationship. You are not obligated to inform him of what happened, and it is permissible to perform Istikhara (prayer for guidance) regarding the permissibility of swearing, as Istikhara is performed for permissible matters.