This song is one of Jiro's singles released in late 2014. 最溫柔的力量 was used in the drama Single's Villa, where Jiro acted in. The song basically describes Jiro's character, how he silently protects the female lead even though he knows she is after someone else.

Rough lyrics translation below:

當你為愛掉眼淚
Dang ni wei ai diao yan lei
When you have to shed tears for love
當你孤單或疲憊
Dang ni gu dan huo pi bei
When you are alone or tired
別害怕一直有我
Bie hai pa yi zhi you wo
Do not be afraid, you always have me
守在天黑的世界
Shou zai tian hei de shi jie
Guarding you in this dark world

不撤退也不會累
Bu che tui ye bu hui lei
Will not retreat, will not be tired
是我愛你的哲學
Shi wo ai ni de zhe xue
Is my philosophy for loving you
隨時準備好肩膀
Shui shi zhun bei hao jian bang
My shoulders are ready anytime
借給你療傷
Jie gei ni liao shang
To lend you to heal

把眼淚都交給我來收藏
Ba yan lei dou jiao gei wo lai shou cang
Give me your tears to keep
在需要的時候給你我的翅膀
Zai xu yao de shi hou gei ni wo de chi bang
The time you need it I will give you my wings

我不能做你的太陽
Wo bu neng zuo ni de tai yang
I cannot be your sun
就做守護你的月光
Jiu zuo shou hu ni de yue guang
I will just guard your moonlight
無條件守在你身旁
Wu tiao jian shou zai ni shen pang
Unconditionally waiting by your side
最溫柔的力量
Zui wen rou de li liang
The most tender strength

雖然不是你的太陽
Sui ran bu shi ni de tai yang
Although I am not your sun
我是守護你的月光
Wo shi shou hu ni de yue guang
I am guarding your moon
不張揚也從不退讓
Bu zhang yang ye cong bu tui rang
Will not show off nor will never retreat
是我愛你溫柔的力量
Shi wo ai ni wen rou de li liang
It is the tender strength that I love

可以勇敢往前飛
Ke yi yong gan wang qian fei
You can be brave before you fly
有我擋住暴風雪
You wo dang zhu bao feng xue
You have me to stop the storm and snow
像個堅強的後衛
Xiang ge jian qiang de hou wei
Like a firm guard
做你心碎的防線
Zuo ni xin sui de fang xian
Defending your broken heart

相信總會有一天
Xiang xin zong hui you yi tian
Believe that there will be a day
你懂月光有多美
Ni dong yue guang you duo mei
You know that the moonlight is beautiful
真愛不需要走遠
Zhen ai bu xu yao zou yuan
True love does not have to be far
就在你身邊
Jiu zai ni shen bian
Just to be beside you

把眼淚都交給我來收藏
Ba yan lei dou jiao gei wo lai shou cang
Give me your tears to keep
在需要的時候給你我的翅膀
Zai xu yao de shi hou gei ni wo de chi bang
The time you need it I will give you my wings

我不能做你的太陽
Wo bu neng zuo ni de tai yang
I cannot be your sun
就做守護你的月光
Jiu zuo shou hu ni de yue guang
I will just guard your moonlight
無條件守在你身旁
Wu tiao jian shou zai ni shen pang
Unconditionally waiting by your side
最溫柔的力量
Zui wen rou de li liang
The most tender strength

雖然不是你的太陽
Sui ran bu shi ni de tai yang
Although I am not your sun
我是守護你的月光
Wo shi shou hu ni de yue guang
I am guarding your moon
不張揚也從不退讓
Bu zhang yang ye cong bu tui rang
Will not publicize nor will never retreat
是我愛你溫柔的力量
Shi wo ai ni wen rou de li liang
It is the tender strength that I love

我不能做你的太陽
Wo bu neng zuo ni de tai yang
I cannot be your sun
就做守護你的月光
Jiu zuo shou hu ni de yue guang
I will just guard your moonlight
無條件守在你身旁
Wu tiao jian shou zai ni shen pang
Unconditionally waiting by your side
最溫柔的力量
Zui wen rou de li liang
The most tender strength

我是守護你的月光
Wo shi shou hu ni de yue guang
I am guarding your moonlight
雖然不是你的太陽
Sui ran bu shi ni de tai yang
Although I am not your sun
讓我保管你的悲傷
Rang wo bao guan ni de bei shang
Let me take care of your sorrows
陪你找到幸福的方向
Pei ni zhao dao xing fu de fang xiang
Be with you in finding the direction of happiness

pinyin lyrics and translation by me

I stopped watching the drama at around episode 10 coz I got annoyed with the mainland accent. Xu Lu is pretty and all, but she got most of the script that her accent annoys me. Jiro doesn't get much exposure in the drama anyway. There were even episodes where he doesn't have any appearance at all. The drama isn't that bad though, but since I'm watching it because of Jiro and I don't see him that much, I lost interest.