英语翻译可以写成口语,也可以是书面语

If you said one hundred times" I could do it",
then you must be OK.

If you could say 'i can do' a hundred times, then you should do that.

If you say "I can" for one hundred times,you can.

If you say "I can" one hundred times, you can for sure.

If you said millions and one times "I can!", you would surely make it!

if you say "i can" for a hundred times, then you will feel really can

If you say "I can" for one hundred times,then you can make it.

我觉得按照国外的习惯应该将重点放在前面。
You can do it if you say "I can" for 100 times

If you talk to youself "I can" one hundred times,you must have the ability to do it.

you can do it if you say "i can" 100 times

If you say "I can" for one hundred times,you can.
you can do it if you say "i can" 100 times