Welcome to 'Just Answer' and thank you for trusting me with your question.
It all depends on how much you DO love them or even if you love them at all. If you're not sure what to say you could turn the question back round to them and say something like "ooooh that's a hard question, how much do you love me?" therefore putting them on the spot.
If you feel you're not ready to tell them you love them then don't, and if you do want to tell them then say how much. "More than life itself". "That much" - and open your arms as wide as you can. It all depends on the way it was said, just be honest with them.
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