Sounds like you have a difficulty getting them mixed up as they sound very different.
Yahtzuvah (עצובה) and tovah (טובה)
Identifying the struggle is half the battle.
I remember עצובה because it sounds like "sooth", someone who is sad needs to be soothed.
I remember טובה by remembering that מזל טוב (mazel tov), which is a hebrew phrase often heard in America that means "congratulations".