What is the ruling on saying "I am as certain of this as I am that God is One" or similar phrases to emphasize a statement? And does the Almighty's saying apply to it: "So do not coin comparisons for Allah"?

If a person is certain of something and wishes to confirm its truth by saying: "Allah is One," then we hope there is no harm in that, and it does not fall under the prohibition in His saying, "So do not set forth similitudes for Allah," because the verse means not likening Allah to inanimate objects or things, for He, the Exalted, has no likeness or peer. The verse came in the context of prohibiting the worship of idols that possess nothing, for Allah knows the realities while you do not. Therefore, the verse has no relation to confirming the mentioned meaning through the affirmation of Allah's Oneness.