By the Lord before whom this sanctuary is holy, I will to N. be true and faithful, and love all which he loves and shun all which he shuns, according to the laws of God and the order of the world. Nor will I ever with will or action, through word or deed, do anything which is unpleasing to him, on condition that he will hold to me as I shall deserve it, and that he will perform everything as it was in our agreement when I submitted myself to him and chose his will.
I basically modified the first sentence, then used a conglomeration of sentences from 12th century homage oaths rather than actual fealty.
By all I hold sacred, I will be true and faithful according to the laws and the order of the world. I will maintain loyalty to thee, and thy heirs, in matters of life and limb and of earthly honor against all mortal men.
Translated word for word using http://www.oldenglishtranslator.co.uk/
Be á ic heald hálignessa, ic gewill béo sóþ ond holdræden endebyrdnesse to sé æriht ond sé worulde níedhæse. Ic gewill hæfest hláfordhylde to þé, ond to úre ierfan, in andweorc æ ond leomu ond eorðfæt ár wiðer á déaþlicnessa menn .
I reversed the word for word translation and got the following:
By all I hold Sacred, I will be true and failthful service according to the code of law and the world order. I will hold loyalty to thee, and to your heir, in matters life and limb and earthly honor against all mortal men.I have no doubt my grammar was "interesting", but thanks to some coaching on site, I was pleased with the delivery of my oath.
I wanted to write my own ceremony and use this to base the acceptence on (I wanted the wergild included), but I ran out of time.
7th century Antrusian
Acceptance of fealty, from Roziere: Collection de Formules, No. VIII, Vol. I (online source)
It is right that those who offer to us unbroken fidelity should be protected by our aid. And since such and such a faithful one of ours, by the favor of God, coming here in our palace with his arms, has seen fit to swear trust and fidelity to us in our hand, therefore we decree and command by the present precept that for the future such and such above mentioned be counted with the number of antrustions. And if anyone perchance should presume to kill him, let him know that he will be judged guilty of his wergild of 600 shillings.
I read a lot, and did not print everything, since I did not originally plan on writing this up, but these were the two internet sources that I found most useful.