Trip.com is a travel booking website that was founded in 1999 in Shanghai, China. Since then, it has expanded its operations to over 200 countries, with headquarters in Shanghai, China, and Singapore. The company offers a range of travel services, including flights, hotels, vacation packages, and activities/tours.

One of the major factors that determine the legitimacy of a travel business is its accreditation and certifications. In this regard, Trip.com has been accredited with several credible certifications, including:

1. International Air Transport Association (IATA) accreditation: IATA is a global trade association representing airlines from around the world. Having IATA accreditation means that Trip.com can issue airline tickets directly.
2. Travelife Gold Certification: Travelife is an international sustainability certification program for the travel industry. The Gold Certification is the highest level of certification that a company can achieve, demonstrating a strong commitment to sustainability practices.
3. Best Online Travel Agency Award 2020 by World Travel Awards: World Travel Awards are considered to be the Oscars of the travel industry, and winning this award is a major endorsement of a travel business’s legitimacy.

In addition to these certifications, Trip.com has received positive reviews from its customers, both on its website and on review platforms such as TripAdvisor. This indicates that the company has a good track record of providing quality services and customer support.

However, like any other travel business, Trip.com has faced some criticism and negative reviews from customers. Some of the common complaints include refunds taking longer than expected, poor customer service, and issues with the booking process. However, it is worth noting that most of these complaints are common among travel businesses and do not necessarily indicate illegitimacy.