'Solemn' in the Bible

"'Then I passed by you and watched you, noticing that you had reached the age for love. I spread my cloak over you and covered your nakedness. I swore a solemn oath to you and entered into a marriage covenant with you, declares the sovereign Lord, and you became mine.

But those in Jerusalem will view it as a false omen. They have sworn solemn oaths, but the king of Babylon will accuse them of violations in order to seize them.