YOU SAID:
I do like watermelons
INTO JAPANESE
私はスイカが好きです
BACK INTO ENGLISH
I like watermelon
INTO JAPANESE
わたしはスイカが好きです。
BACK INTO ENGLISH
I like to eat watermelon.
INTO JAPANESE
わたしはスイカが好きです。
BACK INTO ENGLISH
I like to eat watermelon.
That didn't even make that much sense in English.