As discussed under Mosiah 19:15, the original Book of Mormon text used the noun condition(s) only in the plural (14 times). In five of these cases, however, the plural conditions has been replaced, twice nonpermanently, with the singular condition (the singular is what we expect in modern English). Here in Helaman 14:18, 𝓟 reads in the plural and the 1830 edition has the singular. For this part of the text, both sources are firsthand copies of 𝓞. Although it is theoretically possible that 𝓞 read in the singular, as “the condition of repentance”, it is unlikely since all other instances in the text are in the plural and there has been a rather persistent tendency to change the plural to the singular. It is therefore highly probable that the 1830 typesetter is the one responsible for the variation here in Helaman 14:18. The critical text will restore the original plural.
Summary: Restore in Helaman 14:18 the original plural conditions (“the conditions of repentance”); the original text apparently had no examples of the singular condition.