To be / to get

まるで自分の実の子どものように私の面倒を見てくれた老紳士のことを考えると、感謝の気持ちでいっぱいになります。

(1) When I think of the old gentleman who took care of me like his own child, my heart #gets# filled with gratitude.

(2) When I think of the old gentleman who took care of me like his own child, my heart #is# filled with gratitude.

(3) Whenever I think of the old gentleman who took care of me like his own child, my heart #is# filled with gratitude.

I don't know which to use "gets" or "is" in this sentence.
If I translate「～になる」faithfully, I select "gets" here.
But I feel "is" also makes sense.
At least, if I say "whenever" first like (3), I guess "is" is surely acceptable.

Could you please tell me what you think of my opinions?



Thank you in advance!!!


[Memo: word-usage-context]