{.i .u'u doi la daiv .i .e'anai ku'i mi na curmi le nu do go'i}For this purpose you should use {lo} (using {le} here offers no benifits really. There're almost no practical cases where {le nu} is ever needed.)
{.e'a} (and by extension {.e'anai}) is what we call an "irrealis attitudinal". What that means is that it basically describes a non-real world. {.e'anai do go'i} by *itself* means "I'm not letting you do that," whereas {.e'anai mi na curmi lo nu do go'i} means "I'm not allowing it to not be the case that I allow you to do that," which sounds approximately as semantically wrong in English as it does in Lojban :p.