2 They were from nations about which the LORD had told the Israelites, “You must not intermarry with them, because they will surely turn your hearts after their gods.” Nevertheless, Solomon held fast to them in love.

Read 1 Kings 11:2 Using Other Translations

Of the nations concerning which the LORD said unto the children of Israel, Ye shall not go in to them, neither shall they come in unto you: for surely they will turn away your heart after their gods: Solomon clave unto these in love.
from the nations concerning which the LORD had said to the people of Israel, "You shall not enter into marriage with them, neither shall they with you, for surely they will turn away your heart after their gods." Solomon clung to these in love.
The LORD had clearly instructed the people of Israel, “You must not marry them, because they will turn your hearts to their gods.” Yet Solomon insisted on loving them anyway.