Stories like this are usually either heavily exaggerated or they're hiding details that make the "gift" way less magical. If it actually happened, it's most likely an inheritance that was structured as a gift, or a joint business where the woman was given her share. Rarely, it's stock in a growing company that someone invested in years ago, or a stake in real estate that appreciated over time. Nobody just hands out 48 million for nothing - even super wealthy people usually give way more modestly.
As for whether it's real: sure, it can happen, but only if the person already had a foundation - parents with capital, a lucky marriage to someone genuinely rich, or she invested money there herself earlier. For ordinary people without that foundation, don't count on getting a "gift" like that. It's not luck; it's more that the person was already in a certain social circle.
If you saw a story like this online with a pretty picture and promises to "learn the secret" - that's almost definitely a scam. Real wealth stories look way more boring and require either starting capital or years of work.