I don't have personal experience with the spell but have looked over it.
You cannot seal an angel inside you, that is if angels are even real, it is a very personal belief that some people do not share.
It is always best to think realistically about spells, especially if the person writing the spell cannot spell angel...
If it seems too good to be true, that's because it is, anyhow it is always best to write spells yourself.
