The most reliable personal trainer is YOU, that's not to suggest someone may not be beneficial.
I'm not being sarcastic since I wish you well, yet why does the volume increase exponentially in sports medicine physicians offices, health clubs, AAS forums the list is seemingly endless, after the "first of the year"?
The answer of course is personal resolutions for those with, lifelong, deficient dietary and exercise regimes.
The point is, IF your one of those whom are feeling guilty, understand save your money, because NO "personal trainer" can accomplish the task but you.
If not, there are several means of locating a qualified PT but be aware of the differing levels of training, the QUALIFICATIONS are not uniform, and currently, vary state by state.
PT - certificate; Typically only requires several MONTHS of education and experience.
PT - with an EARNED educational degree. The degree varies from AD to BS or BA.
Most have specialized "training" in sports education or ergonomics.
The degrees range from a BS in kinesiology to AD in physical education. The former is much more desirable IMO.
There are those who obtain a Masters degree in Physical Training, yet most are more involved in the BUSINESS aspect of "sports/exercise facilities".
Which educational degree best compliments your level of expertise is an unknown entity at present, but I would require any "personal trainer" to have a basic certificate unless all I needed was periodic spots, lol!
Jim