What is is saying what the hell a sin?

Saying "what the hell" is not necessarily considered a sin in most religious beliefs. It is generally seen as a mild form of profanity or vulgar language, but it does not typically go against any specific religious teachings or commandments.

However, in some religious traditions, using harsh language or swearing can be considered disrespectful or offensive, and therefore may be discouraged or condemned. It is important to consider the cultural and social context in which the language is used and to show respect for others' beliefs and sensitivities.

Ultimately, whether or not saying "what the hell" is a sin is subjective and may vary depending on individual beliefs and interpretations of religious teachings. It is always best to strive for positivity and kindness in speech and actions.