pls. help me to translate.
konnichiwa,

What is the difference between using the adjective form, as in this example-- ''YASAHII from using this form-- YASAHIKU?''

What is the difference between using the verb form, as in this example -- ''MATSU from using this form MATTE?''

Domo arigatou.

Additional Details:
Konnichiwa,

What is the meaning of ''kanjirunda?''
And what is the use of ''runda'' if follows a certain word, because I often notice it?
What is the meaning of ''da'' that I often notice in a common Japanese grammar, as in ''nanda yo?''

Domo arigatou.

Question

pls. help me to translate.
konnichiwa,

What is the difference between using the adjective form, as in this example-- ''YASAHII from using this form-- YASAHIKU?''

What is the difference between using the verb form, as in this example -- ''MATSU from using this form MATTE?''

Domo arigatou.

Additional Details:
Konnichiwa,

What is the meaning of ''kanjirunda?''
And what is the use of ''runda'' if follows a certain word, because I often notice it?
What is the meaning of ''da'' that I often notice in a common Japanese grammar, as in ''nanda yo?''

Domo arigatou.

Answer

1. ''YASASHII" and "YASASHIKU''
First of all, I guess you mean "yasashii," not "yasahii".

The difference is, well, the "yasashii" is an adjective and "yasashii" is an adverb, as you know :)
So you use "yasashii" to describe how someone is like.
(example)
Kare wa yasashii.= He is gentle.
Watashi wa yasashii hito ga sukidesu. = I like gentle person.

On the other hand, you use "yasashiku" to describe how someone does something.
(example)
Yasashiku oshiemasu.=I teach gently.
Yasashiku shite kudasai.=Do it gently, please.

2. "Matsu" and "Matte"
"Matsu" is the dictionary form, or present affirmative form of verb "wait". "Matte" is "-te form" of "matsu".
If they are used as sentence themselves and there is no other context, 
"Matsu." = I wait.
"Matte."= Wait, please. (abb. of "Matte kudasai")
 
3. "Kanjirunda"
If I separate it into parts, it's "Kanjiru + n + da"
"Kanjiru" is a verb that means to feel.
"-nda" here emphasizes that he/she FEELs something. Or, depending on the context, he/she is explaining the reason his/her former behavior.

"-da" is casual/rough equivalent of "-desu".