''Is absent but hates him''
'mais quelle est cette ...' means but what is this (thing) / who is this (person).
"Mais ce n'est pas le joyeux ..." means "but is is not the merry ..."
Mais cette amitié est à jamais. -- But this friendship is forever.
It means "But French is very difficult"
This isn't a complete sentence, but what you wrote translates to "...'who' but it's okay".
"la vie est dure mais j'aime vivre" means "Life is hard, but I love to live"
In English it means 'but it's okay, life is very beautiful'.
all very beautiful but which one are you?
Speaking of love is hard but I love you.
"tout le monde veut les réponses mais la question est : pourquoi ?"
la vie est très stressante mais je l'aime quand même
it means nothing in Spanish. Spanish is the language they speak in Spain. This is written in French, the language they speak in France. And in French "mais je ne suis pas sur de ce qui est en gras" means: "but I'm not sure about what is [written] in bold [characters]"