I don't think it is fake AT ALL!!!! Nerves will let some people laugh at awkward moments. The bride seems to be one of those that has a great laugh and probably laughs like this quite a bit. Even the groom seems to know that. Not everything out there is fake.
When Dh and I were at our rehearsal he got to the part about the Holy Spirit and he said Holy Spillit!!! Everyone that noticed cracked up and the Pastor kept telling him the rest of the night..."BOY.....Don't you say Holy Spillit tomorrow!!" I remember standing there shaking the rest of the time from trying to hold in the laughter.
Of course DH practiced and practiced all night and over half the time it came out wrong. When the actual ceremony took place and we got to that part we both started laughing and once he finally said the words correctly we laughed again. The pastor let out a sigh of relief and we laughed again. Even after over 20 years of marriage he will still say Holy Spillit when we talk about that day and we still laugh about it.