Explanation

• Successful people always Have two things. One determination and second sincerity.
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• in the above sentence, two events happen, so we use "have" in the sentence.. because have is the best choice to keep the meaning of the original sentence
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• While the verb to have has many different meanings, its primary meaning is “to possess, own, hold for use, or contain.”
• Have and has indicated possession in the present tense (describing events that are currently happening).
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• The verb have has the forms: have, has, having, and had.
• The base form of the verb is have.
• The present participle is having.
• The past tense and past participle forms are had.