Is a person's refusal to utter "I love Allah" because they feel it would be a lie, and then their subsequent reluctance to say it later for fear of lying as well, considered disbelief (kufr) or doubt in their love for Allah? And are these thoughts (waswas) from Satan or are they genuine?

This feeling is a whisper from Satan to turn the servant away from worship and to corrupt their worldly life and their afterlife. The person must disregard these whispers, repel them, and firmly believe in the sincerity of their love for their Lord, because the love of Allah is firmly established in the heart of every believer. It is not permissible to give in to these whispers, as they are among the greatest gates of evil.