Let's break it down:
* Haga me lo saber: This is a combination of the formal "usted" form ("Haga") and the informal "tú" form ("me lo saber"). It's grammatically incorrect, and the meaning is unclear.
* Hágamelo saber: This is the correct way to say "Let me know" in Spanish. It uses the formal "usted" form and is a direct translation of the English phrase.
Therefore, the best translation of "Haga melo saber" is "Let me know."
However, it's crucial to note that the context of the sentence could change the meaning slightly. For example, if someone asks, "Haga me lo saber," it's possible they're asking you to let them know something specific, and the phrase is a mispronunciation of "Hágamelo saber."
If you're unsure of the intended meaning, asking for clarification is always a good idea!