In a medium bowl, combine the diced pineapple, mango, soy sauce, honey, olive oil, minced garlic, grated ginger, black pepper, salt, and lime juice. Mix well and set aside half of the marinade for later use.

Place the chicken breasts in a resealable plastic bag or shallow dish and pour the remaining marinade over the chicken. Seal the bag or cover the dish and refrigerate for at least 30 minutes, or up to 2 hours for more flavor.

Preheat your grill to medium-high heat. Remove the chicken from the marinade and discard the used marinade.

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 the chicken is grilling, heat the reserved marinade in a small saucepan over medium heat until it comes to a simmer. Cook for about 5 minutes, then remove from heat.

Once the chicken is done, let it rest for 5 minutes before slicing. Drizzle the heated marinade over the sliced chicken and garnish with fresh cilantro, if desired.