genial: adjective, means good-tempered or friendly (this is a formal word):
1. friendly and cheerful 友好的；親切的 SYN: affable
It was easy to feel welcome in Henry’s home: he was so genial.
congenial: adjective, means pleasant, and is used by someone of a person or environment that complements their interests, character and outlook on life(less formal alternatives to congenial are pleasant and friendly):
1. (of a person) pleasant to spend time with because their interests and character are similar to your own 意氣相投的贴届，情趣相投的，合得來的
2. (of a place, job, etc) pleasant because it suits your character 相宜的，合意的，適宜的
3. (formal) suitable for sth 適宜的涵妥，適合的
The members of the tennis club were congenial company.
