There is nothing to forgive, if you dont watch anime or read manga like crazy than its confusing.
“chan” is a version of “kun” but mostly used in association with girls. Its used in a way if you have an affection for a girl “soft spot” like “Lara-chan” and you think she is cute. Basically its an expression of cuteness with showing deep affection (love like) with a soft spot.
Regards,
S.