That depends on what kind of suspense you're after. 'Secrets' by Nora Roberts? Or the thriller by someone else? You gotta be specific. My answer is based on the Nora Roberts one, which my mom left at my apartment last summer.
If you're looking for a slow-building, atmospheric suspense wrapped in a contemporary romance frame, yeah, it's worth a few afternoons. The core mystery of the found diary and the decades-old secrets in the small town has its moments. The tension isn't knife-edge; it's more like a steady, creeping dread about what's buried in the town's past and who doesn't want it dug up.
But if you're craving something relentless like a Gillian Flynn or Tana French, you might find the pacing too gentle, too interlaced with the protagonist's romantic subplot and renovating her inherited house. For me, the real suspense wasn't in the 'whodunit' so much as watching the protagonist's safe new world slowly crack open to reveal the rot underneath.
Honestly, I skimmed the romance bits.