Reason is a tool to help us better understand and defend our faith; as Anselm put it, ours is a faith that seeks understanding.

Certainty is an unrealistic and unattainable ideal

I am an Orangeman first and a politician and member of this parliament [Stormont] afterwards.

But the argument is still unsound, because the first premise is false: there are other unmentioned alternatives, for example, that Jesus as described in the gospels is a legendary figure, so that the trilemma is false as it stands.

For the assertion that "There is no God" is just as much a claim to knowledge as is the assertion that "There is a God." Therefore, the former assertion requires justification just as the latter does.

Should a conflict arise between the witness of the Holy Spirit to the fundamental truth of the Christian faith and beliefs based on argument and evidence, then it is the former which must take precedence over the latter.

If you're sincerely seeking God, God will make His existence evident to you.