Let me explain... / Let me put it another way... / What I mean is...
Used when you feel you haven't expressed yourself clearly and want to try again. Shows self-awareness and a desire to communicate better.
Let me put it clearly: it's not that I don't want to, it's that I can't.
Let me explain... what I mean is that there are alternatives.
—I don't understand you. —Let me explain more clearly.