[jon_the_d]

masa,

1).
"I'll" does not necessarily imply future action, it also can imply "habit under certain circumstances".

e.g. "Sometimes when I'm tired, I'll just go to sleep."
"Sometimes when I want to hear your voice, even if I haven't got much to say, I'll give you call"

It covers past, present and future, how you behave in that circumstance.

2).
I know this is "meaning to live/meaning of life", but in English saying a heart is alive does not sound right. The person "lives", the person is "alive", not the heart...

so I made the change to existence. people can also talk about their own "reason to exist". here existence and life are mostly interchangeable, except we would not describe a heart as being alive...or having a life...

again, direct translation may not always work, so I go with what makes sense in English.
The way I have it, using existence, is how an english speaker would say the same sentence.

EDIT: On second thoughts, "life" could be used, but it still sounds strange to me...

Thanks for your comments!