YOU SAID:
she swam in the lake with him because they were all happy
INTO JAPANESE
彼らはみんな幸せだったので、彼女は彼と一緒に湖で泳いだ
BACK INTO ENGLISH
She swam in the lake with him because they were all happy
INTO JAPANESE
彼女は彼と一緒に湖で泳いだのは、彼らがみんな幸せだったので
BACK INTO ENGLISH
She swam in the lake with him because they were all happy
That's deep, man.