知っていればさえいればなぁ。

to be aware of; to know; to be conscious of; to cognize; to cognise; to notice; to feel; to understand; to comprehend; to grasp; to remember; to be acquainted with (a procedure); to experience; to go through; to learn; to be acquainted with (a person); to get to know; to concern

even; if only; if just; as long as; the only thing needed

to need; to want

hey; say; look; used to get someone's attention or press one's point