Do your best Do your best! You can do it you can do it! You can definitely do it! Do your best! You can go farther! You can! It's a matter of passion! Right! Don't give up there! You can definitely do it! Don't give up!
--- Kimochi no mondai sounds weird when translated literally. To me anyway.
Kimochi no mondai comes up twice in the examples in Kenkyusha:
どの程度お礼をするかは気持ちの問題だ。 How much (money) you give depends on how you feel. 今度の事件をどう見るかは受け取る方の気持ちの問題だ。 How one views the latest incident depends on how one feels about it.
So, "It's a matter of passion!" is a valid translation to me, much more than "it's up to your heart." Personally, I'd go with "It's all in the mind!"