눈에서 멀어지면 마음에서 멀어진다 (out of sight out of mind)
멀어지다 [v] recede, become distant, for a distance to increase
마음 - [n] mind, a place in the human body where mental activities such as feeling and thinking occur.
semi-polite: 눈에서 멀어지면 마음에서 멀어진다고 하잖아요
>> This expression is used to express that if you are far away from each other or do not meet often, your feelings for each other will gradually decrease and your relationship will become awkward.
>> This expression comes from the English saying “out of sight out of mind” and has been translated into Korean
>> The expression is used to say no matter how close you are, if you don't see each other often, your relationship will naturally become distant.