I would like to find a term, if it exists, to describe an individual who kids himself. Specifically, the term is to describe someone who does something that is obviously self-deceiving in some sense.
Sam's comment is correct. Either "deluded" or "delusional" is apt. It may easily, however, be deemed offensive because it implies strongly that the person described is insane. A way to say much the same thing without implying general insanity is to use the phrase "fool oneself."
The sentence "Tom is fooling himself if he thinks she can ever forgive him" does not imply that Tom generally fails to recognize reality, but limits his delusion to a specidic situation. It is not overtly insulting although people may feel insulted by being criticized.