I memorize all dialogues in the movie because I've seen it many times.
I've seen the movie so many times that I memorize all dialogues in it.
その映画のセリフは全て暗記してる
memorize, learn by heart
どちらでも良いかと思います。
その映画のすべてのセリフ all dialogues in the movie
何回も観ているので because I've seen it many times
I memorize all dialogues in the movie because I've seen it many times.
so~that構文を使って
I've seen the movie so many times that I memorize all dialogues in it.
I've seen that movie so many times that I've actually memorized everything they say.
この場合は memorize もしくは know が使えます。
すべてのセリフならI've seen that movie so many times that I've actually memorized everything they say (in the movie).
特定のキャラクターのセリフなら I've seen that film so many times that I know all her/his/their lines.
私ならI can quote word for word all the lines in/from that film because I've seen it so many times. を使うと思います。
Can quote word for word = (ミス無しで全てのセリフが)言える
日本 
イギリス 
