Preheat your grill to medium-high heat.
In a medium bowl, combine the diced pineapple, mango, soy sauce, honey, olive oil, minced garlic, ground ginger, black pepper, salt, and lime juice. Mix well to create a marinade.
Place the chicken breasts in a large resealable plastic bag or a shallow dish. Pour half of the marinade over the chicken, ensuring it is well coated. Reserve the other half of the marinade for basting and serving.
Seal the bag or cover the dish and refrigerate for at least 30 minutes, or up to 2 hours for more flavor.
Remove the chicken from the marinade and discard the marinade used for marinating. Place the chicken on the preheated grill.
Grill the chicken for about 6-7 minutes on each side, or until the internal temperature reaches 165°F and the chicken is cooked through.
While grilling, baste the chicken with the reserved marinade for added flavor.
Once cooked, remove the chicken from the grill and let it rest for 5 minutes before slicing.
Serve the grilled chicken topped with the remaining mango and pineapple mixture and garnish with fresh cilantro if desired.