The both of them remember me of the quote "Hatred never ceases by hatred, but by love alone is healed. This is an ancient and eternal law." In both of them the main guy wants revenge and makes the main girl fall in love with him only to hurt her, but he gradually falls in love too.
Main Story is almost similar written by same writer. Sealed with a kiss showed it better because it have more episode to explain the reason behind the main lead extreme reaction also it showed how female lead slowly fall in love with the main lead.
Both deal with a male lead who lost his love and child, blames a woman for it, falls for her while getting revenge. Secret is a little lighter on the abusive side.
These are both intense dramas that feature revenge - as with Secret/Secret Love, the male lead's entire motivation is shaped by a former/first love, and the on/off relationship with the female lead. The actors in both dramas have AMAZING chemistry together, but their parings have some wild moments that make you question their sanity or common sense. If you like dramas with over-the-top and toxic OTPs, this may be right up your alley. Both have some very triggering content (violence, abuse, assault, etc.), so I wouldn't recommend either drama for younger viewers or for those who may be affected by the things listed above.
Both dramas - definitely worth watching. Similar feeling. Main male lead is agreesive and cruel (because of the past, misunderstanding) towards to a female lead and in the end of a drama he discovers he loves her and that she's not as bad as he thought. Final of "Le Jun Kai" is dramatic in comparison with "Kleun Cheewit".