種 and 実: seeds, fruit, and results
Distinguish seeds that are sown, fruit that forms, and figurative outcomes.
Sowing seeds
種 (たね) means seed. 「土に種をまきました」 means sowing seeds in soil.
「種をまいてから一週間たちました」 says a week has passed since sowing. It does not establish that the seeds sprouted.
Fruit forming
実 (み) means fruit. 「木に実がなりました」 says the tree bore fruit.
「実の中に種があります」 locates seeds inside the fruit. Read の中に to identify what contains what.
No guaranteed outcome
「種をまきましたが、芽は出ませんでした」 says seeds were sown but did not sprout. Separate the action from the growth result.
「努力が実を結びました」 figuratively says efforts bore fruit. It is not restricted to actual fruit on a tree.
Does 「種をまきました」 guarantee that sprouts appeared?
Show the answer and why
No. It only reports sowing; germination requires separate confirmation.