please explain what this means its a line by Ojousama character from an anime「[お慕い申しております！どうしても、この気持ちをお伝えしたくて！もしよかったら、わたくしと永遠の契りを あぁー私 (わたくし) ったら、もう何を言ってるんでしょうか？]。
Aside from vocabulary, an analysis of the quote evokes a number of literary conventions, which find their source in traditional Japanese culture.
This seems to be a standard manga or dorama style declaration of the speaker's feelings for another person お慕い申しております (the sentiment) and 気持ちをお伝えしたくて (the confirmation of the speaker's desire to convey said sentiment)
Request -- if the other person would agree もしよかったら -- for "the person's hand in marriage", since official documents are traditionally exchanged, as in a contract or, at least, here, a formal vow, an "eternal promise", i.e. 永遠の契り (which in a different context may connote a more spiritual, even religious commitment).
This declaration/request/"confession" (depending on context) is followed by another standard leitmotif found in manga/dorama, whereby the declaration itself is considered (by the possibly embarrassed speaker -- and perhaps in light of social norms) as an impulsive, or even premature, unexpected revelation of the speaker's private sentiments, even a betrayal of the speaker's own sense of dignity. [Abrupt interruption of declaration/request] あぁー 私 (わたくし)ったら、もう何を言ってるんでしょうか？