This is the 652nd most frequent Korean word.
싶은
"싶은" means "wanting to" or "want to" (used to express desire).
Here, '싶은' modifies '기분' to describe the desire for the action of eating.
나는 파스타가 먹고 싶은 기분이야.
I feel like eating pasta.
In this sentence, '싶은' modifies '마음' to express the want associated with the subject and action.
너와 함께 있고 싶은 마음이 커.
I have a strong desire to be with you.
'싶은' is used here to modify '계획' to indicate a plan related to a desire.