from the bottom of my heart 发自肺腑的
Every word I say to you , I say it from the bottom of my heart !
I want you to know that I really appreciate your support from the bottom of my heart.
真心：wholehearted; heartfelt; sincere; true intention; sincerity; genuineness
sincere words; 真心话
give wholehearted support to; 真心拥护
1、【wholehearted】If you support or agree to something in a wholehearted way, you support or agree to it enthusiastically and completely. 全心全意的
The governor deserves our wholehearted support for having taken a step in this direction.
2、【heartfelt】Heartfelt is used to describe a deep or sincere feeling or wish. 衷心的
My heartfelt sympathy goes out to all the relatives.
3、【sincere】If you say that someone is sincere, you approve of them because they really mean the things they say. You can also describe someone's behaviour and beliefs as sincere. (指人) 真诚的; (指行为、信仰) 诚挚的，表赞许
He's sincere in his views.
It's hard to discern his 【true intention】 in such a short period of time.
4、【genuineness】the state of being genuine 真实，真正；真诚，真挚
1）is used to describe people and things that are exactly what they appear to be, and are not false or an imitation. 真正的
There was a risk of genuine refugees being returned to Vietnam.
2）If you describe a person as genuine, you approve of them because they are honest, truthful, and sincere in the way they live and in their relationships with other people. 诚实可靠的
She is very caring and very genuine.
3）Genuine refers to things such as emotions that are real and not pretended. 真诚的
If this offer is genuine, I will gladly accept it.