a euphemism is a substitution for an expression that may offend or suggest something unpleasant to the receiver, using instead an agreeable or less offensive expression ,or to make it less troublesome for the speaker. I think this is the word u were looking for..
Euphorism refers to the use of positive and uplifting language or affirmations to promote feelings of well-being and happiness. It involves expressing optimism, gratitude, and joy in thoughts, words, and actions. Euphorism can help improve mental health and promote a positive outlook on life.