Is there any tool that can help us learn openings by heart? I tried to use Fritz but without success.
Two well-known programs that are meant specifically to aid in the memorization of opening variations are
Both programs are designed to recognize and handle transpositions seamlessly, and they allow a player to drill all the positions that are part of any repertoires that he or she inputs.
Chessable is famous for learning chess openings by the MoveTrainer space repetition. Check out MoveTrainer at https://www.chessable.com/movetrainer.