"You have also given me the shield of Your salvation; Your right hand has held me up, Your gentleness has made me great." NKJV
Gentleness is not weak or passive, Jesus said in Matt 11:28-30 "Come to me for I am gentle and humble in heart and that's where you will find rest for your souls." Gentleness is non-threatening, tender and humble, and comes from a position of strength.
In Philippians 4:5 we are told to "Let your gentleness be evident to all." I experienced this when I was in India. The women that I met in the church there had this beatiful gift of gentleness. It was lovely to be in their presence as they quietly worked nearby and served us with humility.
When I respond with a gentle answer to other people, I've found they more readily receive my reply. One incident where this happened, I was waiting in a very long queue at an airport and a man behind me was insisting that he should be in front of me. He wanted to get ahead in the queue and was becoming quite hostile. I decided it was much easier to gently stand aside and let him go ahead than to confront him. So I smiled sweetly and said, "please take your place in front of me". He did so, and calmed down.
I didn't feel I was giving in to his demands as I had chosen to react to him in a gentle way. We see in Proverbs 15:1 that "a gentle answer turns away wrath, but a harsh word stirs up anger." Jesus also said, "What do you prefer? Shall I come to you with a whip, or in love and with a gentle spirit." Cor 4:21.