Will Reset > Delete Data and Settings, prevent recovering my Data? if I am planning to sell my iPhone?

Any determined hacker can get an awful lot of data off of just about any data storage device. The catch here is, does Apple make it just difficult enough for the average, non-government, hacker to spend more time and money getting the data off your iPhone or SSD than it is worth?

Generally speaking that unless you are carrying information worth tens of thousands of dollars in your iPhone then it is unlikely that it is worth the time, effort and money to recover the data.

Is is POSSIBLE? The answer will (almost) always be yes, unless you want to feed your old iPhone through a metal shredder.

Is it at all LIKELY? The answer will (almost) always be no.

It is a decision only you can make but if the information is only valuable to you then the likelihood of anyone getting any usable information off your iPhone is slim at best. And the built-in wipe feature is sufficient to protect your personal data.