From my experience, fact that someone has not verified their payment method doesn't have to imply that it's an untrusted client/job offer. Personally, I (although seldomly) apply to such jobs if there's something about them that really interests me and fits my skill set. During the interview phase I gave the client links to how to set up a verified payment method and they did so, relatively quickly, and I got those jobs and had a good experience.
With unverified method of payment I look at the following - when did the client join (if recently then it can make sense), how many jobs they posted (better if this is the first one or in case more exist they are posted around the same time) and the job description (now this can be tricky - I prefer well-detailed job descriptions because that should indicate the person is really looking to get the job done and knows what needs to be done, but it could also be a fellow freelancer just fishing for good cover letters).
With verified payment, look BEYOND their star-rating, actually do the work and read the feedback they got. If they left a bad feedback to someone go to that freelancer's profile and see what the client said about them (if the freelancer's profile no longer exists that could mean your client was not wrong), look at their hiring rate (the higher the better). Also, not less important, look at how much they pay (average hr rate and amount spent on how many contracts) to get an idea of whether you have a match between what they want and offer and what you deem your work is worth.
Also, a hint for when you are contemplating what rate to offer and worry you might scare them off - check out some previous job posts they posted and how much the job post offered and what they ended up paying that freelancer - it could give you a relatively accurate estimate of how much they're willing to "budge" and pay for quality.
Hope this helps! I know having all of this listed in one place would've helped me when I started out 🙂
Cheers!
